Enhanced packing of energy storage particles

ABSTRACT

The present application is generally directed to energy storage materials such as activated carbon comprising enhanced particle packing properties and devices containing the same. The energy storage materials find utility in any number of devices, for example, in electric double layer capacitance devices and batteries. Methods for making the energy storage materials are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.13/250,430, which was filed on Sep. 30, 2011, now allowed, which claimsthe benefit under 35 U.S.C. §119(e) of U.S. Provisional PatentApplication No. 61/388,388 filed on Sep. 30, 2010; which application isincorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The present invention generally relates to the packing of energy storageparticles, for example activated carbon particles, as well as tocompositions and devices containing such particles and methods relatedto the same.

2. Description of the Related Art

Energy storage materials are commonly employed in electrical storage anddistribution devices. For example, devices containing particles ofactivated carbon, silicon, sulfur, lithium, and combinations thereof, asenergy storage media are ubiquitous throughout the electrical industry.Of these, activated carbon particles find particular use in a number ofdevices because the high surface area, conductivity and porosity ofactivated carbon allows for the design of electrical devices havinghigher energy density than devices employing other materials.

Electric double-layer capacitors (EDLCs) are an example of devices thatcontain activated carbon particles. EDLCs often have electrodes preparedfrom an activated carbon material and a suitable electrolyte, and havean extremely high energy density compared to more common capacitors.Typical uses for EDLCs include energy storage and distribution indevices requiring short bursts of power for data transmissions, orpeak-power functions such as wireless modems, mobile phones, digitalcameras and other hand-held electronic devices. EDLCs are also commonlyused in electric vehicles such as electric cars, trains, buses and thelike.

Batteries are another common energy storage and distribution devicewhich often contain activated carbon particles (e.g., as anode material,current collector, or conductivity enhancer). Examples ofcarbon-containing batteries include lithium air batteries, which useporous carbon as the current collector for the air electrode, and leadacid batteries which often include carbon additives in either the anodeor cathode. Batteries are employed in any number of electronic devicesrequiring low current density electrical power (as compared to an EDLC'shigh current density).

An important characteristic to be considered in the design of electricalstorage and distribution devices comprising activated carbon particlesis volumetric performance. For example, in many of the devices describedabove, size is a constraint, and the physical size of the electrode islimited. Thus, high volumetric capacitance (i.e., capacitance per unitvolume) is a desired characteristic of an electrode and the EDLCcomprising the electrode(s). Volumetric capacitance of an EDLC isbelieved to be, at least in part, related to the efficiency of theactivated carbon particle packing within the electrode. As the carbonparticle packing approaches an optimum value (i.e., theoretical maximumnumber of carbon particles per unit volume), the inter-particle volumeis minimized, and the volumetric capacitance of the EDLC electrode isexpected to increase. This same principle is believed to apply to othertypes of energy storage particles and electrical devices containing thesame.

Current methods for preparing activated carbon particles do not resultin activated carbon particles having a particle size distribution whichprovides for optimized particle packing. One common method for producinghigh surface area activated carbon material is to pyrolyze an existingcarbon-containing material (e.g., coconut fibers or tire rubber).Activated carbon materials can also be prepared by chemical activation.For example, treatment of a carbon-containing material with an acid,base or salt (e.g., phosphoric acid, potassium hydroxide, sodiumhydroxide, zinc chloride, etc.) followed by heating results in anactivated carbon material. Another approach for producing high surfacearea activated carbon materials is to prepare a synthetic polymer fromcarbon-containing organic building blocks. As with the existing organicmaterials, the synthetically prepared polymers are pyrolyzed andactivated to produce an activated carbon material. In contrast to thetraditional approach described above, the intrinsic porosity of thesynthetically prepared polymer results in higher process yields becauseless material is lost during the activation step.

The activated carbon particles prepared according to the above methodsmay be further processed to reduce the particle size. Such methodsinclude milling, such as ball milling, cryo-milling and bead milling, aswell as crushing. While these methods may improve the particle packingover the unprocessed carbon material, current applications of suchmethods are not sufficient to provide an activated carbon materialhaving a particle size distribution which provides for optimizedparticle packing.

While significant advances have been made in the field, there continuesto be a need in the art for energy storage materials, for exampleactivated carbon particles, comprising a particle size distributionwhich provides for optimized particle packing, as well as for methods ofmaking the same and devices containing the same. The present inventionfulfills these needs and provides further related advantages.

BRIEF SUMMARY

In general terms, the present invention is directed to energy storagematerials comprising a plurality of energy storage particles. In oneparticular embodiment, the energy storage material is activated carbonand the energy storage particles are activated carbon particles. In thisembodiment, the plurality of carbon particles comprises a particle sizedistribution such that particle packing is optimized relative to otherknown carbon materials. Such optimized particle packing allows forpreparation of carbon electrodes comprising packing densities andvolumetric performance not previously obtainable. Accordingly, thedisclosed carbon materials find application in the context of electricalstorage and distribution devices, particularly for use in electrodes forEDLCs and batteries having improved volumetric performance.

Accordingly, in one embodiment, an energy storage material is provided,the energy storage material comprising a plurality of energy storageparticles, wherein the plurality of energy storage particles comprises aparticle size distribution such that the equation of a plot of thecumulative finer volume distribution vs. particle size comprises acorrelation coefficient of 0.96 or greater relative to the modifiedAndreassen equation for the particle size distribution, and wherein themodified Andreassen equation comprises a q value of 0.3.

In other embodiments, the present disclosure provides an energy storagematerial comprising a plurality of energy storage particles, wherein theplurality of energy storage particles comprises a packing ratio of 0.97or greater when formed into an electrode.

In still other embodiment, the present disclosure is directed a carbonmaterial having a calendaring ratio of at least 40% when combined with abinder and formed into an electrode.

In yet other embodiments, the disclosure provides a carbon materialcomprising a plurality of carbon particles, wherein the carbon particlescomprise a trimodal particle size distribution having first, second andthird particle size maxima, wherein the first particle size maximum isat about 0.1 μm to about 0.2 μm, the second particle size maximum is atabout 0.9 to about 1.0 μm and the third particle size maximum is atabout 9 μm to about 10 μm.

In another embodiment, a device comprising a carbon material isprovided. The carbon material comprises a plurality of carbon particles,the plurality of carbon particles comprising a particle sizedistribution such that the equation of a plot of the cumulative finervolume distribution vs. particle size comprises a correlationcoefficient of 0.96 or greater relative to the modified Andreassenequation for the particle size distribution, and wherein the modifiedAndreassen equation comprises a q value of 0.3.

In other embodiments, the present disclosure is directed to an electrodecomprising a carbon material, wherein the carbon material comprises aplurality of carbon particles, the plurality of carbon particlescomprising a particle size distribution such that the equation of a plotof the cumulative finer volume distribution vs. particle size comprisesa correlation coefficient of 0.96 or greater relative to the modifiedAndreassen equation for the particle size distribution, and wherein themodified Andreassen equation comprises a q value of 0.3.

In other embodiments, the present disclosure provides an electrodeconsisting essentially of a binder and an amorphous carbon materialhaving a surface area of at least 1,500 M²/g.

In still other embodiments, the disclosure is directed to an electrodehaving a thickness D μm and comprising a carbon material comprising aplurality of carbon particles, wherein the carbon particles have apacking ratio of at least 0.97 when combined with a binder and formedinto an electrode, and the plurality of carbon particles comprises atrimodal particle size distribution comprised of a first collection ofparticles having a mean particle size A μm, a second collection ofparticles having a mean particle size B μm and a third collection ofparticles having a mean particle size C μm, wherein A:B and B:C are eachbetween about 100:1 and 2:1 and D:A is between about 2:1 and 100:1.

In still other embodiments, the present disclosure provides a method forpreparing a carbon material comprising a plurality of carbon particles,the plurality of carbon particles comprising a particle sizedistribution such that the equation of a plot of the cumulative finervolume distribution vs. particle size comprises a correlationcoefficient of 0.96 or greater relative to the modified Andreassenequation for the particle size distribution, and wherein the modifiedAndreassen equation comprises a q value of 0.3, the method comprising:

a) providing two or more carbon samples, each carbon sample comprising aunique particle size distribution; and

b) blending the two or more carbon samples at a predetermined ratio toobtain the carbon material.

BRIEF DESCRIPTION OF THE DRAWINGS

In the figures, identical reference numbers identify similar elements.The sizes and relative positions of elements in the figures are notnecessarily drawn to scale and some of these elements are arbitrarilyenlarged and positioned to improve figure legibility. Further, theparticular shapes of the elements as drawn are not intended to conveyany information regarding the actual shape of the particular elements,and have been solely selected for ease of recognition in the figures.

FIG. 1A shows particle size distributions (PSD) for a representative(prior art) milled, activated carbon material. FIG. 1B shows that themeasured PSD (solid-line) diverges from the optimal PSD (dashed-line)according to the modified Andreassen equation with a q value of 0.3.

FIG. 2A shows the PSD of a milled, activated carbon material. FIG. 2Bshows the PSD of the milled, activated carbon material of FIG. 2A uponfurther milling.

FIG. 3A shows the PSD of an approximately 40:60 blend of two differentcarbon materials. FIG. 3B shows the predicted correlation coefficient ofa blended mixture at different blend ratios. FIG. 3C shows that themeasured PSD (solid-line) of the blend is approaching the optimal PSD(dashed-line) according to the modified Andreassen equation with a qvalue of 0.3.

FIG. 4A is an overlay showing the PSD of the carbon material of FIG. 1A(solid-line) and the carbon material of FIG. 2B (dashed-line). FIG. 4Bshows the PSD of a blend of the carbon material of FIG. 1A and thecarbon material of FIG. 2B. FIG. 4C shows that the measured PSD(solid-line) of the blend further approaches the optimal PSD(dashed-line) according to the modified Andreassen equation with a qvalue of 0.3.

FIG. 5A is an overlay showing the PSD of the carbon material of FIG. 1A(solid-line), the carbon material of FIG. 2A (dashed-line) and thecarbon material of FIG. 2B (dotted-line). FIG. 5B shows the PSD of ablend of the carbon material of FIG. 1A, the carbon material of FIG. 2Aand the carbon material of FIG. 2B. FIG. 5C shows that the measured PSD(solid-line) of the blend is close to the optimal PSD (dashed-line)according to the modified Andreassen equation with a q value of 0.3.

FIG. 6 shows the particle size distribution of two different milledcarbon samples.

FIG. 7 shows the calculated correlation coefficient of a blended carbonmaterial relative to the modified Andreassen equation at different blendratios.

FIG. 8 is the particle size distribution of a control carbon sample.

FIG. 9 presents the particle size distribution of a carbon samplecollected from a jet milling operation.

FIG. 10 is a graph showing the particle size distribution of a controlcarbon sample compared to the particle size distribution for theAndreassen equation.

FIG. 11 shows the particle size distribution of a carbon samplecollected from a jet milling operation compared to the particle sizedistribution for the Andreassen equation.

FIG. 12 demonstrates high correlation between the particle sizedistribution of an optimized carbon blend according to the presentinvention compared to the particle size distribution for the Andreassenequation.

FIGS. 13A and 13B are TEM images of electrodes prepared with a controlcarbon and an optimized blended carbon, respectively.

FIG. 14 presents volumetric capacitance data for electrodes preparedfrom a control carbon and an optimized carbon blend.

FIG. 15 is a graph showing gravimetric capacitance for electrodesprepared from a control carbon and an optimized carbon blend.

DETAILED DESCRIPTION

In the following description, certain specific details are set forth inorder to provide a thorough understanding of various embodiments.However, one skilled in the art will understand that the invention maybe practiced without these details. In other instances, well-knownstructures have not been shown or described in detail to avoidunnecessarily obscuring descriptions of the embodiments. Unless thecontext requires otherwise, throughout the specification and claimswhich follow, the word “comprise” and variations thereof, such as,“comprises” and “comprising” are to be construed in an open, inclusivesense, that is, as “including, but not limited to.” Further, headingsprovided herein are for convenience only and do not interpret the scopeor meaning of the claimed invention.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure or characteristicdescribed in connection with the embodiment is included in at least oneembodiment. Thus, the appearances of the phrases “in one embodiment” or“in an embodiment” in various places throughout this specification arenot necessarily all referring to the same embodiment. Furthermore, theparticular features, structures, or characteristics may be combined inany suitable manner in one or more embodiments. Also, as used in thisspecification and the appended claims, the singular forms “a,” “an,” and“the” include plural referents unless the content clearly dictatesotherwise. It should also be noted that the term “or” is generallyemployed in its sense including “and/or” unless the content clearlydictates otherwise.

Definitions

As used herein, and unless the context dictates otherwise, the followingterms have the meanings as specified below.

“Energy storage material” refers to a material capable of storingelectrical charge, for example in the form of physically entrainedelectrolytes. Energy storage materials are capable of being charged anddischarged. Examples of energy storage materials include, but are notlimited to, carbon, for example activated carbon, silicon, sulfur,lithium, and combinations thereof. Energy storage materials may be usedin the form of particles, or combinations of inter- and/orintra-particle blends of particles. Energy storage particles can beassembled into electrodes employing dry processing or aqueous ornon-aqueous slurry processing as described in the art.

“Carbon material” refers to a material or substance comprisedsubstantially of carbon. Examples of carbon materials include, but arenot limited to, activated carbon, pyrolyzed dried polymer gels,pyrolyzed polymer cryogels, pyrolyzed polymer xerogels, pyrolyzedpolymer aerogels, activated dried polymer gels, activated polymercryogels, activated polymer xerogels, activated polymer aerogels and thelike.

“Conductivity enhancer” is a carbon material which is commonly added tocarbon electrodes to increase electrochemical performance of theelectrode. Conductivity enhancers are generally submicron sizedparticles of carbon with low pore volume. Examples of conductivityenhancers include graphite and carbon black.

“Packing Ratio” is defined as the inverse of the electrode densitydivided by the sum of the inverse of the skeletal denisity of the carbon(typically 2.2 g/cc) and the pore volume as measured using nitrogensorption. A packing ratio of 1.0 would indicate that optimized packinghas been achieved. A packing ratio of less than one indicates that lessthan optimum packing has been achieved, and a packing ratio of greaterthan one indicates that packing is optimized beyond that expected basedon the mass and volume of the combined electrode components.

“Impurity” or “impurity element” refers to a foreign substance (e.g., achemical element) within a material which differs from the chemicalcomposition of the base material. For example, an impurity in a carbonmaterial refers to any element or combination of elements, other thancarbon, which is present in the carbon material. Impurity levels aretypically expressed in parts per million (ppm).

“PIXE impurity” is any impurity element having an atomic number rangingfrom 11 to 92 (i.e., from sodium to uranium). The phrases “total PIXEimpurity content” and “total PIXE impurity level” both refer to the sumof all PIXE impurities present in a sample, for example, a polymer gelor a carbon material. PIXE impurity concentrations and identities may bedetermined by proton induced x-ray emission (PIXE).

“Ash content” refers to the nonvolatile inorganic matter which remainsafter subjecting a substance to a high decomposition temperature.Herein, the ash content of a carbon material is calculated from thetotal PIXE impurity content as measured by proton induced x-rayemission, assuming that nonvolatile elements are completely converted toexpected combustion products (i.e., oxides).

“Polymer” refers to a macromolecule comprised of two or more structuralrepeating units.

“Synthetic polymer precursor material” or “polymer precursor” refers tothe compounds used in the preparation of a synthetic polymer. Examplesof polymer precursors that can be used in the preparations disclosedherein include, but are not limited to aldehydes (i.e., HC(═O)R, where Ris an organic group), such as for example, methanal (formaldehyde);ethanal (acetaldehyde); propanal (propionaldehyde); butanal(butyraldehyde); glucose; benzaldehyde and cinnamaldehyde. Otherexemplary polymer precursors include, but are not limited to, phenoliccompounds such as phenol and polyhydroxy benzenes, such as dihydroxy ortrihydroxy benzenes, for example, resorcinol (i.e., 1,3-dihydroxybenzene), catechol, hydroquinone, and phloroglucinol. Mixtures of two ormore polyhydroxy benzenes are also contemplated within the meaning ofpolymer precursor.

“Monolithic” refers to a solid, three-dimensional structure that is notparticulate in nature.

“Sol” refers to a colloidal suspension of precursor particles (e.g.,polymer precursors), and the term “gel” refers to a wetthree-dimensional porous network obtained by condensation or reaction ofthe precursor particles.

“Polymer gel” refers to a gel in which the network component is apolymer; generally a polymer gel is a wet (aqueous or non-aqueous based)three-dimensional structure comprised of a polymer formed from syntheticprecursors or polymer precursors.

“Sol gel” refers to a sub-class of polymer gel where the polymer is acolloidal suspension that forms a wet three-dimensional porous networkobtained by reaction of the polymer precursors.

“Polymer hydrogel” or “hydrogel” refers to a subclass of polymer gel orgel wherein the solvent for the synthetic precursors or monomers iswater or mixtures of water and one or more water-miscible solvent.

“RF polymer hydrogel” refers to a sub-class of polymer gel wherein thepolymer was formed from the catalyzed reaction of resorcinol andformaldehyde in water or mixtures of water and one or morewater-miscible solvent.

“Acid” refers to any substance that is capable of lowering the pH of asolution. Acids include Arrhenius, Brønsted and Lewis acids. A “solidacid” refers to a dried or granular compound that yields an acidicsolution when dissolved in a solvent. The term “acidic” means having theproperties of an acid.

“Base” refers to any substance that is capable of raising the pH of asolution. Bases include Arrhenius, Brønsted and Lewis bases. A “solidbase” refers to a dried or granular compound that yields basic solutionwhen dissolved in a solvent. The term “basic” means having theproperties of a base.

“Mixed solvent system” refers to a solvent system comprised of two ormore solvents, for example, two or more miscible solvents. Examples ofbinary solvent systems (i.e., containing two solvents) include, but arenot limited to: water and acetic acid; water and formic acid; water andpropionic acid; water and butyric acid and the like. Examples of ternarysolvent systems (i.e., containing three solvents) include, but are notlimited to: water, acetic acid, and ethanol; water, acetic acid andacetone; water, acetic acid, and formic acid; water, acetic acid, andpropionic acid; and the like. The present invention contemplates allmixed solvent systems comprising two or more solvents.

“Miscible” refers to the property of a mixture wherein the mixture formsa single phase over certain ranges of temperature, pressure, andcomposition.

“Catalyst” is a substance which alters the rate of a chemical reaction.Catalysts participate in a reaction in a cyclic fashion such that thecatalyst is cyclically regenerated. The present disclosure contemplatescatalysts which are sodium free. The catalyst used in the preparation ofa polymer gel as described herein can be any compound that facilitatesthe polymerization of the polymer precursors to form a polymer gel. A“volatile catalyst” is a catalyst which has a tendency to vaporize at orbelow atmospheric pressure. Exemplary volatile catalysts include, butare not limited to, ammoniums salts, such as ammonium bicarbonate,ammonium carbonate, ammonium hydroxide, and combinations thereof.

“Solvent” refers to a substance which dissolves or suspends reactants(e.g., polymer precursors) and provides a medium in which a reaction mayoccur. Examples of solvents useful in the preparation of the polymergels and carbon materials disclosed herein include, but are not limitedto, water, alcohols and mixtures thereof. Exemplary alcohols includeethanol, t-butanol, methanol and mixtures thereof. Such solvents areuseful for dissolution of the synthetic polymer precursor materials, forexample dissolution of a phenolic or aldehyde compound. In addition, insome processes such solvents are employed for solvent exchange in apolymer hydrogel (prior to freezing and drying), wherein the solventfrom the polymerization of the precursors, for example, resorcinol andformaldehyde, is exchanged for a pure alcohol. In one embodiment of thepresent application, a cryogel is prepared by a process that does notinclude solvent exchange.

“Dried gel” or “dried polymer gel” refers to a gel or polymer gel,respectively, from which the solvent, generally water, or mixture ofwater and one or more water-miscible solvents, has been substantiallyremoved.

“Pyrolyzed dried polymer gel” refers to a dried polymer gel which hasbeen pyrolyzed but not yet activated, while an “activated dried polymergel” refers to a dried polymer gel which has been activated.

“Cryogel” refers to a dried gel that has been dried by freeze drying.Analogously, a “polymer cryogel” is a dried polymer gel that has beendried by freeze drying.

“RF cryogel” or “RF polymer cryogel” refers to a dried gel or driedpolymer gel, respectively, that has been dried by freeze drying whereinthe gel or polymer gel was formed from the catalyzed reaction ofresorcinol and formaldehyde.

“Pyrolyzed cryogel” or “pyrolyzed polymer cryogel” is a cryogel orpolymer cryogel, respectively, that has been pyrolyzed but not yetactivated.

“Activated cryogel” or “activated polymer cryogel” is a cryogel orpolymer cryogel, respectively, which has been activated to obtainactivated carbon material.

“Xerogel” refers to a dried gel that has been dried by air drying, forexample, at or below atmospheric pressure. Analogously, a “polymerxerogel” is a dried polymer gel that has been dried by air drying.

“Pyrolyzed xerogel” or “pyrolyzed polymer xerogel” is a xerogel orpolymer xerogel, respectively, that has been pyrolyzed but not yetactivated.

“Activated xerogel” or “activated polymer xerogel” is a xerogel orpolymer xerogel, respectively, which has been activated to obtainactivated carbon material.

“Aerogel” refers to a dried gel that has been dried by supercriticaldrying, for example, using supercritical carbon dioxide. Analogously, a“polymer aerogel” is a dried polymer gel that has been dried bysupercritical drying.

“Pyrolyzed aerogel” or “pyrolyzed polymer aerogel” is an aerogel orpolymer aerogel, respectively, that has been pyrolyzed but not yetactivated.

“Activated aerogel” or “activated polymer aerogel” is an aerogel orpolymer aerogel, respectively, which has been activated to obtainactivated carbon material.

“Organic extraction solvent” refers to an organic solvent added to apolymer hydrogel after polymerization of the polymer precursors hasbegun, generally after polymerization of the polymer hydrogel iscomplete.

“Rapid multi-directional freezing” refers to the process of freezing apolymer gel by creating polymer gel particles from a monolithic polymergel, and subjecting said polymer gel particles to a suitably coldmedium. The cold medium can be, for example, liquid nitrogen, nitrogengas, or solid carbon dioxide. During rapid multi-directional freezingnucleation of ice dominates over ice crystal growth. The suitably coldmedium can be, for example, a gas, liquid, or solid with a temperaturebelow about −10° C. Alternatively, the suitably cold medium can be agas, liquid, or solid with a temperature below about −20° C.Alternatively, the suitably cold medium can be a gas, liquid, or solidwith a temperature below about −30° C.

“Activate” and “activation” each refer to the process of heating a rawmaterial or carbonized/pyrolyzed substance at an activation dwelltemperature during exposure to oxidizing atmospheres (e.g. carbondioxide, oxygen, or steam) to produce an “activated” substance (e.g.activated cryogel or activated carbon material). The activation processgenerally results in a stripping away of the surface of the particles,resulting in an increased surface area. Alternatively, activation can beaccomplished by chemical means, for example, by impregnation ofcarbon-containing precursor materials with chemicals such as acids likephosphoric acid or bases like potassium hydroxide, sodium hydroxide orsalts like zinc chloride, followed by carbonization. “Activated” refersto a material or substance, for example a carbon material, which hasundergone the process of activation.

“Carbonizing”, “pyrolyzing”, “carbonization” and “pyrolysis” each referto the process of heating a carbon-containing substance at a pyrolysisdwell temperature in an inert atmosphere (e.g., argon or nitrogen) or ina vacuum such that the targeted material collected at the end of theprocess is primarily carbon. “Pyrolyzed” refers to a material orsubstance, for example a carbon material, which has undergone theprocess of pyrolysis.

“Dwell temperature” refers to the temperature of the furnace during theportion of a process which is reserved for maintaining a relativelyconstant temperature (i.e., neither increasing nor decreasing thetemperature). For example, the pyrolysis dwell temperature refers to therelatively constant temperature of the furnace during pyrolysis, and theactivation dwell temperature refers to the relatively constanttemperature of the furnace during activation.

“Pore” refers to an opening or depression in the surface, or a tunnel ina carbon material, such as for example activated carbon, pyrolyzed driedpolymer gels, pyrolyzed polymer cryogels, pyrolyzed polymer xerogels,pyrolyzed polymer aerogels, activated dried polymer gels, activatedpolymer cryogels, activated polymer xerogels, activated polymer aerogelsand the like. A pore can be a single tunnel or connected to othertunnels in a continuous network throughout the structure.

“Pore structure” refers to the layout of the surface of the internalpores within a carbon material, such as an activated carbon material.Components of the pore structure include pore size, pore volume, surfacearea, density, pore size distribution, and pore length. Generally thepore structure of activated carbon material comprises micropores andmesopores.

“Mesopore” generally refers to pores having a diameter between about 2nanometers and about 50 nanometers while the term “micropore” refers topores having a diameter less than about 2 nanometers. Mesoporous carbonmaterials comprise greater than 50% of their total pore volume inmesopores while microporous carbon materials comprise greater than 50%of their total pore volume in micropores. “Surface area” refers to thetotal specific surface area of a substance measurable by the BETtechnique. Surface area is typically expressed in units of m²/g. The BET(Brunauer/Emmett/Teller) technique employs an inert gas, for examplenitrogen, to measure the amount of gas adsorbed on a material and iscommonly used in the art to determine the accessible surface area ofmaterials.

“Connected” when used in reference to mesopores and micropores refers tothe spatial orientation of such pores.

“Effective length” refers to the portion of the length of the pore thatis of sufficient diameter such that it is available to accept salt ionsfrom the electrolyte.

“Electrode” refers to a conductor through which electricity enters orleaves an object, substance, or region.

“Binder” refers to a material capable of holding individual particles ofcarbon together such that after mixing a binder and carbon together theresulting mixture can be formed into sheets, pellets, disks or othershapes. Non-exclusive examples of binders include fluoro polymers, suchas, for example, PTFE (polytetrafluoroethylene, Teflon), PFA(perfluoroalkoxy polymer resin, also known as Teflon), FEP (fluorinatedethylene propylene, also known as Teflon), ETFE(polyethylenetetrafluoroethylene, sold as Tefzel and Fluon), PVF(polyvinyl fluoride, sold as Tedlar), ECTFE(polyethylenechlorotrifluoroethylene, sold as Halar), PVDF(polyvinylidene fluoride, sold as Kynar), PCTFE(polychlorotrifluoroethylene, sold as Kel-F and CTFE), trifluoroethanoland combinations thereof.

“Inert” refers to a material that is not active in the electrolyte, thatis it does not absorb a significant amount of ions or change chemically,e.g., degrade.

“Conductive” refers to the ability of a material to conduct electronsthrough transmission of loosely held valence electrons.

“Electrolyte” means a substance containing free ions such that thesubstance is electrically conductive. Examples of electrolytes include,but are not limited to, solvents such as propylene carbonate, ethylenecarbonate, butylene carbonate, dimethyl carbonate, methyl ethylcarbonate, diethyl carbonate, sulfolane, methylsulfolane, acetonitrileor mixtures thereof in combination with solutes such astetralkylammonium salts such as TEA TFB (tetraethylammoniumtetrafluoroborate), MTEATFB (methyltriethylammonium tetrafluoroborate),EMITFB (1 ethyl-3-methylimidazolium tetrafluoroborate),tetraethylammonium, triethylammonium based salts or mixtures thereof. Insome embodiments, the electrolyte can be a water-based acid orwater-based base electrolyte such as mild aqueous sulfuric acid oraqueous potassium hydroxide.

As noted above, the present disclosure provides in some embodiments, anenergy storage material comprising a plurality of energy storageparticles, wherein the plurality of energy storage particles comprises aparticle size distribution such that the equation of a plot of thecumulative finer volume distribution vs. particle size comprises acorrelation coefficient of 0.96 or greater relative to the modifiedAndreassen equation for the particle size distribution, and wherein themodified Andreassen equation comprises a q value of 0.3. For example insome embodiments, the energy storage material is a carbon material.

In other embodiments, the correlation coefficient of the energy storagematerial, for example a carbon material, is 0.97 or greater or even 0.99or greater.

In some other embodiments, the energy storage material is a carbonmaterial, and the carbon material comprises a packing ratio of 0.97 orgreater when formed into an electrode. For example, in some embodimentsthe carbon material comprises a packing ratio of 1.0 or greater, or even1.1 or greater, when formed into an electrode.

In yet other embodiments, the energy storage material is a carbonmaterial and the particle size distribution comprises particle sizesranging from 0.01 μm to 20 μm. For example, in some embodiments theparticle size distribution comprises particle sizes ranging from 0.03 μmto 17 μm or from 0.04 μm to 12 μm.

In some other embodiments, the energy storage material is a carbonmaterial, and the carbon material is prepared by blending two or moredifferent carbon samples, each carbon sample comprising a differentparticle size distribution. For example, in some embodiments the carbonmaterial is prepared by blending three different carbon samples.

In some embodiments, the energy storage material is a carbon material,the carbon material is activated, and the carbon material comprises aplurality of activated carbon particles. In yet other embodiments, thecarbon material comprises a plurality of activated carbon particles anda plurality of carbon black particles.

In yet other embodiments, the energy storage material is a carbonmaterial, and the carbon material comprises a total impurity content ofless than 500 ppm of elements having atomic numbers ranging from 11 to92 as measured by proton induced x-ray emission.

In still other embodiments, the energy storage material is a carbonmaterial, and the carbon material comprises a BET specific surface areaof 1500 m²/g or greater, 2000 m²/g or greater or even 2400 m²/g orgreater.

In other embodiments, the energy storage material is a carbon material,and the carbon material comprises a pore volume of at least 0.7 cc/g, atleast 0.8 cc/g, at least 1.0 cc/g, at least 1.3 cc/g, at least 1.5 cc/g,at least 1.8 cc/g or at least 2.0 cc/g.

In some embodiments, the energy storage material comprises a pluralityof carbon particles, wherein the carbon material comprises a trimodalparticle size distribution. For example, in some embodiments thetrimodal particle size distribution comprises particle size maxima atabout 0.1 to about 0.2 μm, about 0.9 to about 1.0 μm and about 9 toabout 10 μm.

In some embodiments, the energy storage material comprises a pluralityof carbon particles, wherein the carbon material comprises a calendaringratio of at least 40% for example at least 50% or at least 60%.

In some other embodiments of the present disclosure, an energy storagematerial is provided, the energy storage material comprising a pluralityof energy storage particles, wherein the plurality of energy storageparticles comprises a packing ratio of 0.97 or greater when formed intoan electrode.

In some further embodiments of the foregoing, the energy storagematerial is a carbon material. For example, in some embodiments thecarbon material comprises a packing ratio of 1.0 or greater when formedinto an electrode.

In other embodiments, the disclosure provides a carbon material having acalendaring ratio of at least 40% when combined with a binder and formedinto an electrode.

In still other embodiments, the disclosure precedes a carbon materialcomprising a plurality of carbon particles, wherein the carbon particlescomprise a trimodal particle size distribution having first, second andthird particle size maxima, wherein the first particle size maximum isat about 0.1 to about 0.2 μm, the second particle size maximum is atabout 0.9 to about 1.0 μm and the third particle size maximum is atabout 9 to about 10 μm.

In other embodiments, the present disclosure provides a devicecomprising a carbon material, wherein the carbon material comprises aplurality of carbon particles, the plurality of carbon particlescomprising a particle size distribution such that the equation of a plotof the cumulative finer volume distribution vs. particle size comprisesa correlation coefficient of 0.96 or greater relative to the modifiedAndreassen equation for the particle size distribution, and wherein themodified Andreassen equation comprises a q value of 0.3. For example, insome embodiments the device is an electric double layer capacitor (EDLC)device comprising;

a) a positive electrode and a negative electrode, wherein each of thepositive and negative electrodes comprise the carbon material;

b) an inert porous separator; and

c) an electrolyte;

wherein the positive electrode and the negative electrode are separatedby the inert porous separator.

In other embodiments, the device is an EDLC, and the EDLC devicecomprises a volumetric capacitance of 5.0 F/cc or greater as measured byconstant current discharge from 2.7 V to 0.1 V with a 5 second timeconstant employing a 1.8 M solution oftetraethylammonium-tetrafluoroborate in acetonitrile electrolyte and acurrent density of 0.5 A/g. In some other embodiments of the foregoing,the volumetric capacitance is 10.0 F/cc or greater, 15.0 F/cc orgreater, 20.0 F/cc or greater, 21.0 F/cc or greater, 22.0 F/cc orgreater or 23.0 F/cc or greater.

In still other embodiments, the device is an EDLC, and the EDLC devicecomprises a gravimetric capacitance of 104 F/g or greater as measured byconstant current discharge from 2.7 V to 0.1 V with a 5 second timeconstant employing a 1.8 M solution oftetraethylammonium-tetrafluoroborate in acetonitrile electrolyte and acurrent density of 0.5 A/g.

In some other embodiments, the device is an EDLC, and the correlationcoefficient is 0.97 or greater or even 0.99 or greater.

In other embodiments, the device is an EDLC, and the carbon materialcomprises a packing ratio of 0.97 or greater when formed into thepositive electrode or the negative electrode. For example, in someembodiments the carbon material comprises a packing ratio of 1.0 orgreater, or even 1.1 or greater, when formed into the positive electrodeor the negative electrode.

In some other embodiments, the device is an EDLC, and the particle sizedistribution comprises particle sizes ranging from 0.01 μm to 20 μm. Inother embodiments, the particle size distribution comprises particlesizes ranging from 0.03 μm to 17 μm or from 0.04 μm to 12 μm.

In still other embodiments, the device is an EDLC, and the carbonmaterial is prepared by blending two or more different carbon samples,each carbon sample comprising a different particle size distribution.For example, in some embodiments the carbon material is prepared byblending three different carbon samples.

In yet other embodiments, the device is an EDLC, and the carbon materialis activated, and the carbon material comprises a plurality of activatedcarbon particles. In other embodiments, the nergy storage materialcomprises a carbon material comprising a plurality of activated carbonparticles and a plurality of carbon black particles.

In some embodiments, the device is an EDLC, and the carbon materialcomprises a total impurity content of less than 500 ppm of elementshaving atomic numbers ranging from 11 to 92 as measured by protoninduced x-ray emission.

In some other embodiments, the device is an EDLC, and the carbonmaterial comprises a BET specific surface area of 1500 m²/g or greater,2000 m²/g or greater or even 2400 m²/g or greater.

In yet some other embodiments, the device is an EDLC, and the carbonmaterial comprises a pore volume of at least 0.7 cc/g, at least 0.8cc/g, at least 1.0 cc/g, at least 1.3 cc/g, at least 1.5 cc/g, at least1.8 cc/g or at least 2.0 cc/g.

In some other embodiments, the device is a battery. For example, in someembodiments the battery is a lithium/carbon battery, lithium ionbattery, lithium sulfur battery, zinc/carbon battery, lithium airbattery or lead acid battery.

In other embodiments, the present disclosure provides an electrodecomprising a carbon material and a binder, wherein the carbon materialcomprises a plurality of carbon particles, the plurality of carbonparticles comprising a particle size distribution such that the equationof a plot of the cumulative finer volume distribution vs. particle sizecomprises a correlation coefficient of 0.96 or greater relative to themodified Andreassen equation for the particle size distribution, andwherein the modified Andreassen equation comprises a q value of 0.3. Insome embodiments, the electrode consists essentially of the carbonmaterial and the binder, for example the electrode may comprise lessthan 0.1% conductivity enhancer.

In still other embodiments, the present disclosure is directed to anelectrode consisting essentially of a binder and an amorphous carbonmaterial having a surface area of at least 1,500 M²/g. For example, insome embodiments the electrode comprises less than 0.1% conductivityenhancer.

In other embodiments, the disclosure provides a carbon based electrodehaving a volumetric capacitance of 15.0 F/cc or greater as measured byconstant current discharge from 2.7 V to 0.1 V with a 5 second timeconstant employing a 1.8 M solution oftetraethylammonium-tetrafluoroborate in acetonitrile electrolyte and acurrent density of 0.5 A/g.

In yet more embodiments, the present disclosure provides an electrodehaving a thickness D μm and comprising a carbon material comprising aplurality of carbon particles, wherein the carbon particles have apacking ratio of at least 0.97 when combined with a binder and formedinto an electrode, and the plurality of carbon particles comprises atrimodal particle size distribution comprised of a first collection ofparticles having a mean particle size A μm, a second collection ofparticles having a mean particle size B μm and a third collection ofparticles having a mean particle size C μm, wherein A:B and B:C are eachbetween about 100:1 and 2:1 and D:A is between about 2:1 and 100:1.

In still other embodiments, the present disclosure provides a method forpreparing a carbon material comprising a plurality of carbon particles,the plurality of carbon particles comprising a particle sizedistribution such that the equation of a plot of the cumulative finervolume distribution vs. particle size comprises a correlationcoefficient of 0.96 or greater relative to the modified Andreassenequation for the particle size distribution, and wherein the modifiedAndreassen equation comprises a q value of 0.3, the method comprising:

a) providing two or more carbon samples, each carbon sample comprising aunique particle size distribution; and

b) blending the two or more carbon samples at a predetermined ratio toobtain the carbon material.

In some embodiments of the method, two or more carbon samples areprepared by milling. For example, in one embodiment at least one carbonsample is prepared by jet milling, while in other embodiments, at leastone carbon sample is subjected to two or more jet milling treatments.

In some embodiments of the method, three carbon samples are blended toobtain the carbon material.

In other embodiments of the method, the predetermined ratio iscalculated by:

a) determining the particle size distribution of each carbon sample; and

b) using the determined particle size distribution of each carbon sampleto calculate the ratio of each carbon sample required to obtain themaximum correlation coefficient.

A. Preparation of Carbon Materials

Carbon materials for use as energy storage particles may be preparedaccording to any number of methods. In one embodiment, the disclosedcarbon materials are prepared by a sol gel process wherein a polymer gelis prepared by polymerization of one or more polymer precursors. Theresulting polymer gel is then dried, for example by rapidly freezingpolymer gel particles followed by lyophilization. The dried polymer gelis then pyrolyzed and optionally activated. The carbon sample thusobtained may then be milled to obtain a desired particle sizedistribution and then blended at a predetermined ratio with one or moreother carbon samples having different particle size distributions toobtain a carbon material having enhanced packing properties. Similarmethods of milling and blending may be employed with other types ofenergy storage particles to enhance the packing properties, and thusvolumetric performance, of the same. Details of the preparation ofcarbon materials of the various embodiments are described below and inco-owned U.S. Pat. No. 7,723,262 and U.S. patent application Ser. No.12/829,282 both of which are hereby incorporated by reference in theirentirety.

1. Preparation of Polymer Gels

The polymer gels may be prepared by a sol gel process. For example, thepolymer gel may be prepared by co-polymerizing one or more polymerprecursors in an appropriate solvent. In one embodiment, the one or morepolymer precursors are co-polymerized under acidic conditions. In someembodiments, a first polymer precursor is a phenolic compound and asecond polymer precursor is an aldehyde compound. In another embodimentof the method, the phenolic compound is resorcinol, catechol,hydroquinone, phloroglucinol, phenol, or a combination thereof; and thealdehyde compound is formaldehyde, acetaldehyde, propionaldehyde,butyraldehyde, benzaldehyde, cinnamaldehyde, or a combination thereof.In a further embodiment, the phenolic compound is resorcinol,phloroglucinol, phenol or a combination thereof, and the aldehydecompound is formaldehyde. In yet further embodiments, the phenoliccompound is resorcinol and the aldehyde compound is formaldehyde.

The sol gel polymerization process is generally performed undercatalytic conditions. Accordingly, in some embodiments, preparing thepolymer gel comprises co-polymerizing one or more polymer precursors inthe presence of a catalyst. In some embodiments, the catalyst comprisesa basic volatile catalyst. For example, in one embodiment, the basicvolatile catalyst comprises ammonium carbonate, ammonium bicarbonate,ammonium acetate, ammonium hydroxide, or combinations thereof. In afurther embodiment, the basic volatile catalyst is ammonium carbonate.In another further embodiment, the basic volatile catalyst is ammoniumacetate.

The molar ratio of catalyst to phenolic compound may have an effect onthe final properties of the polymer gel as well as the final propertiesof the carbon materials prepared therefrom. Thus, in some embodimentssuch catalysts are used in the range of molar ratios of 10:1 to 2000:1phenolic compound:catalyst. In some embodiments, such catalysts can beused in the range of molar ratios of 20:1 to 200:1 phenoliccompound:catalyst. For example in other embodiments, such catalysts canbe used in the range of molar ratios of 25:1 to 100:1 phenoliccompound:catalyst.

The reaction solvent is another process parameter that may be varied toobtain the desired properties of the polymer gels and carbon materialsprepared therefrom. In some embodiments, the solvent for preparation ofthe polymer gel is a mixed solvent system of water and a miscibleco-solvent. For example, in certain embodiments the solvent comprises awater miscible acid. Examples of water miscible acids include, but arenot limited to, propionic acid, acetic acid, and formic acid. In furtherembodiments, the solvent comprises a ratio of water-miscible acid towater of 99:1, 90:10, 75:25, 50:50, 25:75, 10:90 or 1:90. In otherembodiments, acidity is provided by adding a solid acid to the reactionsolvent.

In some other embodiments of the foregoing, the solvent for preparationof the polymer gel is acidic. For example, in certain embodiments thesolvent comprises acetic acid. For example, in one embodiment, thesolvent is 100% acetic acid. In other embodiments, a mixed solventsystem is provided, wherein one of the solvents is acidic. For example,in one embodiment of the method, the solvent is a binary solventcomprising acetic acid and water. In further embodiments, the solventcomprises a ratio of acetic acid to water of 99:1, 90:10, 75:25, 50:50,25:75, 10:90 or 1:90. In other embodiments, acidity is provided byadding a solid acid to the reaction solvent.

In some embodiments of the methods described herein, the molar ratio ofphenolic precursor to catalyst is from about 10:1 to about 2000:1 or themolar ratio of phenolic precursor to catalyst is from about 20:1 toabout 200:1. In further embodiments, the molar ratio of phenolicprecursor to catalyst is from about 25:1 to about 100:1. In furtherembodiments, the molar ratio of phenolic precursor to catalyst is fromabout 25:1 to about 50:1. In further embodiments, the molar ratio ofphenolic precursor to catalyst is from about 100:1 to about 50:1.

In the specific embodiment wherein one of the polymer precursors isresorcinol and another polymer precursor is formaldehyde, the resorcinolto catalyst ratio can be varied to obtain the desired properties of theresultant polymer gel and carbon materials prepared therefrom. In someembodiments of the methods described herein, the molar ratio ofresorcinol to catalyst is from about 10:1 to about 2000:1 or the molarratio of resorcinol to catalyst is from about 20:1 to about 200:1. Infurther embodiments, the molar ratio of resorcinol to catalyst is fromabout 25:1 to about 100:1. In further embodiments, the molar ratio ofresorcinol to catalyst is from about 25:1 to about 50:1. In furtherembodiments, the molar ratio of resorcinol to catalyst is from about100:1 to about 50:1.

Polymerization to form a polymer gel can be accomplished by variousmeans described in the art. For instance, polymerization can beaccomplished by incubating suitable polymer precursor materials in thepresence of a suitable catalyst for a period of time. The time forpolymerization can be a period ranging from minutes or hours to days,depending on temperature (the higher the temperature the faster, thereaction rate, and correspondingly, the shorter the time required). Thepolymerization temperature can range from room temperature to atemperature approaching (but lower than) the boiling point of thestarting solution. For example, the temperature can range from about 20°C. to about 90° C. In the specific embodiment wherein one polymerprecursor is resorcinol and one polymer precursor is formaldehyde, thetemperature can range from about 20° C. to about 100° C., typically fromabout 25° C. to about 90° C. In some embodiments, polymerization can beaccomplished by incubation of suitable synthetic polymer precursormaterials in the presence of a catalyst for at least 24 hours at about90° C. Generally polymerization can be accomplished in between about 6and about 24 hours at about 90° C., for example between about 18 andabout 24 hours at about 90° C.

The polymer precursor materials as disclosed herein include (a)alcohols, phenolic compounds, and other mono- or polyhydroxy compoundsand (b) aldehydes, ketones, and combinations thereof. Representativealcohols in this context include straight chain and branched, saturatedand unsaturated alcohols. Suitable phenolic compounds includepolyhydroxy benzene, such as a dihydroxy or trihydroxy benzene.Representative polyhydroxy benzenes include resorcinol (i.e.,1,3-dihydroxy benzene), catechol, hydroquinone, and phloroglucinol.Mixtures of two or more polyhydroxy benzenes can also be used. Phenol(monohydroxy benzene) can also be used. Representative polyhydroxycompounds include sugars, such as glucose, and other polyols, such asmannitol. Aldehydes in this context include: straight chain saturatedaldeydes such as methanal (formaldehyde), ethanal (acetaldehyde),propanal (propionaldehyde), butanal (butyraldehyde), and the like;straight chain unsaturated aldehydes such as ethenone and other ketenes,2-propenal (acrylaldehyde), 2-butenal (crotonaldehyde), 3 butenal, andthe like; branched saturated and unsaturated aldehydes; andaromatic-type aldehydes such as benzaldehyde, salicylaldehyde,hydrocinnamaldehyde, and the like. Suitable ketones include: straightchain saturated ketones such as propanone and 2 butanone, and the like;straight chain unsaturated ketones such as propenone, 2 butenone, and3-butenone (methyl vinyl ketone) and the like; branched saturated andunsaturated ketones; and aromatic-type ketones such as methyl benzylketone (phenylacetone), ethyl benzyl ketone, and the like. The polymerprecursor materials can also be combinations of the precursors describedabove.

In some embodiments, one polymer precursor is an alcohol-containingspecies and another polymer precursor is a carbonyl-containing species.The relative amounts of alcohol-containing species (e.g. alcohols,phenolic compounds and mono- or poly-hydroxy compounds or combinationsthereof) reacted with the carbonyl containing species (e.g. aldehydes,ketones or combinations thereof) can vary substantially. In someembodiments, the ratio of alcohol-containing species to aldehyde speciesis selected so that the total moles of reactive alcohol groups in thealcohol-containing species is approximately the same as the total molesof reactive carbonyl groups in the aldehyde species. Similarly, theratio of alcohol-containing species to carbonyl species may be selectedso that the total moles of reactive alcohol groups in the alcoholcontaining species is approximately the same as the total moles ofreactive carbonyl groups in the carbonyl species. The same general 1:1molar ratio holds true when the carbonyl-containing species comprises acombination of an aldehyde species and a carbonyl species.

The total solids content in the aqueous solution prior to polymer gelformation can be varied. The weight ratio of resorcinol to water is fromabout 0.05 to 1 to about 0.70 to 1. Alternatively, the ratio ofresorcinol to water is from about 0.15 to 1 to about 0.6 to 1.Alternatively, the ratio of resorcinol to water is from about 0.15 to 1to about 0.35 to 1. Alternatively, the ratio of resorcinol to water isfrom about 0.25 to 1 to about 0.5 to 1. Alternatively, the ratio ofresorcinol to water is from about 0.3 to 1 to about 0.4 to 1.

Examples of solvents useful in the preparation of the polymer gelsdisclosed herein include but are not limited to water or alcohol suchas, for example, ethanol, t-butanol, methanol or mixtures of these,optionally further with water. Such solvents are useful for dissolutionof the polymer precursor materials, for example dissolution of thephenolic compound. In addition, in some processes such solvents areemployed for solvent exchange in the polymer gel (prior to freezing anddrying), wherein the solvent from the polymerization of the precursors,for example, resorcinol and formaldehyde, is exchanged for a purealcohol. In one embodiment of the present application, a polymer gel isprepared by a process that does not include solvent exchange.

Suitable catalysts in the preparation of polymer gels include volatilebasic catalysts that facilitate polymerization of the precursormaterials into a monolithic polymer. The catalyst can also comprisevarious combinations of the catalysts described above. In embodimentscomprising phenolic compounds, such catalysts can be used in the rangeof molar ratios of 20:1 to 200:1 phenolic compound:catalyst. Forexample, in some specific embodiments such catalysts can be used in therange of molar ratios of 25:1 to 100:1 phenolic compound:catalyst.

2. Creation of Polymer Gel Particles

A monolithic polymer gel can be physically disrupted to create smallerparticles according to various techniques known in the art. Theresultant polymer gel particles generally have an average diameter ofless than about 30 mm, for example, in the size range of about 1 mm toabout 25 mm, or between about 1 mm to about 5 mm or between about 0.5 mmto about 10 mm. Alternatively, the size of the polymer gel particles canbe in the range below about 1 mm, for example, in the size range ofabout 10 to 1000 microns. Techniques for creating polymer gel particlesfrom monolithic material include manual or machine disruption methods,such as sieving, grinding, milling, or combinations thereof. Suchmethods are well-known to those of skill in the art. Various types ofmills can be employed in this context such as roller, bead, and ballmills and rotary crushers and similar particle creation equipment knownin the art.

In a specific embodiment, a roller mill is employed. A roller mill hasthree stages to gradually reduce the size of the gel particles. Thepolymer gels are generally very brittle for a ‘wet’ material and are notdamp to the touch. Consequently they are easily milled using thisapproach, however, the width of each stage must be set appropriately toachieve the targeted final mesh. This adjustment is made and validatedfor each combination of gel recipe and mesh size. Each gel is milled viapassage through a sieve of known mesh size. Sieved particles can betemporarily stored in sealed containers.

In one embodiment, a rotary crusher is employed. The rotary crusher hasa screen mesh size of about ⅛^(th) inch. In another embodiment, therotary crusher has a screen mesh size of about ⅜^(th) inch. In anotherembodiment, the rotary crusher has a screen mesh size of about ⅝^(th)inch. In another embodiment, the rotary crusher has a screen mesh sizeof about ⅜^(th) inch.

Milling can be accomplished at room temperature according to methodswell known to those of skill in the art. Alternatively, milling can beaccomplished cryogenically, for example by co-milling the polymer gelwith solid carbon dioxide (dry ice) particles. In this embodiment, thetwo steps of (a) creating particles from the monolithic polymer gel and(b) rapid, multidirectional freezing of the polymer gel are accomplishedin a single process.

3. Rapid Freezing of Polymer Gels

After the polymer gel particles are formed from the monolithic polymergel, freezing of the polymer gel particles is accomplished rapidly andin a multi-directional fashion. Freezing slowly and in a unidirectionalfashion, for example by shelf freezing in a lyophilizer, results indried material having a very low surface area. Similarly, snap freezing(i.e., freezing that is accomplished by rapidly cooling the polymer gelparticles by pulling a deep vacuum) also results in a dried materialhaving a low surface area. As disclosed herein rapid freezing in amultidirectional fashion can be accomplished by rapidly lowering thematerial temperature to at least about −10° C. or lower, for example,−20° C. or lower, or for example, to at least about −30° C. or lower.Rapid freezing of the polymer gel particles creates a fine ice crystalstructure within the particles due to widespread nucleation of icecrystals, but leaves little time for ice crystal growth. This provides ahigh specific surface area between the ice crystals and the hydrocarbonmatrix, which is necessarily excluded from the ice matrix.

The concept of extremely rapid freezing to promote nucleation overcrystal growth can be applied to mixed solvent systems. In oneembodiment, as the mixed solvent system is rapidly cooled, the solventcomponent that predominates will undergo crystallization at itsequilibrium melting temperature, with increased concentration of theco-solvent(s) and concomitant further freezing point depression. As thetemperature is further lowered, there is increased crystallization ofthe predominant solvent and concentration of co-solvent(s) until theeutectic composition is reached, at which point the eutectic compositionundergoes the transition from liquid to solid without further componentconcentration nor product cooling until complete freezing is achieved.In the specific case of water and acetic acid (which as pure substancesexhibit freezing points of 0° C. and 17° C., respectively), the eutecticcomposition is comprised of approximately 59% acetic acid and 41% waterand freezes at about −27° C. Accordingly, in one embodiment, the mixedsolvent system is the eutectic composition, for example, in oneembodiment the mixed solvent system comprises 59% acetic acid and 41%water.

4. Drying of Polymer Gels

In one embodiment, the frozen polymer gel particles containing a fineice matrix are lyophilized under conditions designed to avoid collapseof the material and to maintain fine surface structure and porosity inthe dried product. Details of the conditions of the lyophilization areprovided herein. Generally drying is accomplished under conditions wherethe temperature of the product is kept below a temperature that wouldotherwise result in collapse of the product pores, thereby enabling thedried material to retain an extremely high surface area.

One benefit of having an extremely high surface area in the driedproduct is the improved utility of the polymer gel for the purpose offabrication of capacitors, energy storage devices, and otherenergy-related applications. Different polymer gel applications requirevariations in the pore size distribution such as different levels ofmicropore volume, mesopore volume, surface area, and pore size. Bytuning the various processing parameters of the polymer gel, high porevolumes can be reached at many different pore sizes depending on thedesired application.

The structure of the final carbon material is reflected in the structureof the dried polymer gel which in turn is established by the polymer gelproperties. These features can be created in the polymer gel using asol-gel processing approach as described herein, but if care is nottaken in removal of the solvent, then the structure is not preserved. Itis of interest to both retain the original structure of the polymer geland modify its structure with ice crystal formation based on control ofthe freezing process. In some embodiments, prior to drying the aqueouscontent of the polymer gel is in the range of about 50% to about 99%. Incertain embodiments, upon drying the aqueous content of the polymercryogel is less than about 30%, alternatively less than about 20%,alternatively less than about 10%, alternately less than about 5% orless than about 2.5%.

5. Pyrolysis and Activation of Polymer Gels

The polymer gels may be further processed by pyrolysis and optionalactivation. In this respect, either dried or wet polymer gels (i.e., notdried) may be pyrolyzed. The resulting carbon materials comprise a highsurface area. For example, in some embodiments of the presentdisclosure, a carbon material having a specific surface area of at least150 m²/g, at least 250 m²/g, at least 400 m²/g, at least 500 m²/g, atleast 600 m²/g, at least 700 m²/g, at least 800 m²/g, at least 900 m²/g,at least 1000 m²/g, at least 1500 m²/g, at least 2000 m²/g, at least2400 m²/g, at least 2500 m²/g or at least 3000 m²/g is provided.

Generally, in the pyrolysis process, dried polymer gels are weighed andplaced in a rotary kiln. The temperature ramp is set at 5° C. perminute, the dwell time and dwell temperature are set; cool down isdetermined by the natural cooling rate of the furnace. The entireprocess is usually run under an inert atmosphere, such as a nitrogenenvironment. Pyrolyzed samples are then removed and weighed. Otherpyrolysis processes are well known to those of skill in the art.

In some embodiments, pyrolysis dwell time (i.e., the period of timeduring which the sample is at the desired temperature) is from about 0minutes to about 120 minutes, from about 0 minutes to about 60 minutes,from about 0 minutes to about 30 minutes, from about 0 minutes to about10 minutes, from about 0 to 5 minutes or from about 0 to 1 minute.

Pyrolysis may also be carried out more slowly than described above. Forexample, in one embodiment the pyrolysis is carried out in about 120 to480 minutes. In other embodiments, the pyrolysis is carried out in about120 to 240 minutes.

In some embodiments, pyrolysis dwell temperature ranges from about 500°C. to about 1800° C. In other embodiments pyrolysis dwell temperatureranges from about 550° C. to about 1200° C. In other embodimentspyrolysis dwell temperature ranges from about 600° C. to about 800° C.In other embodiments pyrolysis dwell temperature ranges from about 650°C. to about 900° C.

In some embodiments, the pyrolysis dwell temperature is varied duringthe course of pyrolysis. In one embodiment, the pyrolysis is carried outin a rotary kiln with separate distinct heating zones, the temperaturefor each zone is sequentially decreased from the entrance to the exitend of the rotary kiln tube. In one embodiment, the pyrolysis is carriedout in a rotary kiln with separate distinct heating zones, thetemperature for each zone is sequentially increased from entrance toexit end of the rotary kiln tube.

In some embodiments, the pyrolyzed carbon materials are not furtheractivated, while in other embodiments the carbon materials are furtheractivated to obtain an activated carbon material. Activation time andactivation temperature both have a large impact on the performance ofthe resulting activated carbon material, as well as the manufacturingcost thereof. Increasing the activation temperature and the activationdwell time results in higher activation percentages, which generallycorrespond to the removal of more material compared to lowertemperatures and shorter dwell times. Activation temperature can alsoalter the pore structure of the carbon where lower temperatures resultin more microporous carbon and higher temperatures result inmesoporosity. This is a result of the activation gas diffusion limitedreaction that occurs at higher temperatures and reaction kinetic drivenreactions that occur at lower temperature. Higher activation percentageoften increases performance of the final activated carbon, but it alsoincreases cost by reducing overall yield. Improving the level ofactivation corresponds to achieving a higher performance product at alower cost.

Pyrolyzed polymer gels may be activated by contacting the pyrolyzedpolymer gel with an activating agent. Many gases are suitable foractivating, for example gases which contain oxygen. Non-limitingexamples of activating gases include carbon dioxide, carbon monoxide,steam, and oxygen. Activating agents may also include corrosivechemicals such as acids, bases or salts (e.g., phosphoric acid,potassium hydroxide, sodium hydroxide, zinc chloride, etc.). Otheractivating agents are known to those skilled in the art.

Generally, in the activation process, samples are weighed and placed ina rotary kiln, for which the automated gas control manifold is set toramp at a 20° C. per minute. Carbon dioxide is introduced to the kilnenvironment for a period of time once the proper activation temperaturehas been reached. After activation has occurred, the carbon dioxide isreplaced by nitrogen and the kiln is cooled down. Samples are weighed atthe end of the process to assess the level of activation. Otheractivation processes are well known to those of skill in the art. Insome of the embodiments disclosed herein, activation temperatures mayrange from 800° C. to 1300° C. In another embodiment, activationtemperatures may range from 800° C. to 1050° C. In another embodiment,activation temperatures may range from about 850° C. to about 950° C.One skilled in the art will recognize that other activationtemperatures, either lower or higher, may be employed.

In some embodiments, the activation time is between 1 minute and 48hours. In other embodiments, the activation time is between 1 minute and24 hours. In other embodiments, the activation time is between 5 minutesand 24 hours. In other embodiments, the activation time is between 1hour and 24 hours. In further embodiments, the activation time isbetween 12 hours and 24 hours. In certain other embodiments, theactivation time is between 30 min and 4 hours. In some furtherembodiments, the activation time is between 1 hour and 2 hours.

The degree of activation is measured in terms of the mass percent of thepyrolyzed dried polymer gel that is lost during the activation step. Inone embodiment of the methods described herein, activating comprises adegree of activation from 5% to 90%; or a degree of activation from 10%to 80%; in some cases activating comprises a degree of activation from40% to 70%, or a degree of activation from 45% to 65%.

6. Milling and Blending of Carbon Materials

As noted above, the disclosed carbon materials comprise improvedparticle packing properties. While not wishing to be bound by theory, itis believed that such improved particle packing is due, at least inpart, to the specific particle size distribution of the carbon particleswithin the carbon material. Carbon samples comprising the desiredparticle size distributions can be prepared by any number of methodsknown in the art. In particular, the desired particle size distributionscan be obtained by various milling techniques. The particle sizedistribution obtained from a particular milling operation is a functionof the mill type, the parameters of the milling operation and/or thematerial being milled. The present inventors have found that all ofthese factors can be controlled to obtain the desired particle sizedistribution, and thus optimized packing, as described below.

In some embodiments, the disclosed carbon material is milled to anaverage particle size of about 10 microns. The milling may be performedusing a jetmill operating in a nitrogen atmosphere. While not wishing tobe bound by theory, it is believed that this fine particle size enhancesparticle-to-particle conductivity, as well as enabling the production ofvery thin sheet electrodes. The jetmill essentially grinds the carbonagainst itself by spinning it inside a disc shaped chamber propelled byhigh-pressure nitrogen. As the larger particles are fed in, thecentrifugal force pushes them to the outside of the chamber. As theygrind against each other, the particles migrate towards the center wherethey eventually exit the grinding chamber once they have reached theappropriate dimensions.

In some embodiments, the desired particle size distribution is obtainedby varying the length of time which the carbon material is subjected tomilling conditions. In some other embodiments, rather than increasingthe length of the milling operation, the carbon material may be milledin one operation and then isolated. The isolated carbon material maythen be milled again under identical or different conditions to obtain atwice-milled carbon material. Such twice-milled carbon materialscomprise particle size distributions different (e.g., larger percentageof smaller particles) from carbon samples which have been milled onlyonce.

Other methods for obtaining the desired particle size distribution ofthe disclosed carbon materials include: ball milling, cryo-milling, beadmilling, crushing and the like. Methods which sort and separate carbonparticles having different dimensions, for example sieving or gasclassification systems, may also be employed in the practice of theinvention. Such methods are well known to those skilled in the art.

In some embodiments of the present disclosure, the carbon material isprocessed according to the above procedures to obtain a particle sizedistribution comprising carbon particles ranging from 0.01 μm to 50 μm,from 0.01 μm to 20 μm, from 0.03 μm to 17 μm or from 0.04 μm to 12 μm.Such particle size distributions can be determined using any number oftechniques known to those skilled in the art. In one particularembodiment, the particle size distribution is determined by laserdiffraction techniques. For example, the carbon particles may besuspended in an aqueous solution and the particle size distributiondetermined by laser diffraction.

While the above description uses activated carbon particles as anexample, one skilled in the art will recognize that analogous processesmay be employed to prepare other energy storage particles comprisingimproved packing properties.

B. Energy Storage Particles Having Improved Particle Packing Properties

Enhanced packing of energy storage particles, for example carbonparticles, can be beneficial for a variety of applications. For example,activated carbon materials comprising high surface areas are routinelyused in energy storage devices such as capacitors, particularlysupercapacitors. Typically such high-surface area carbon materials tendto have low densities, and thus their capacitance on a volume basis(i.e., volumetric capacitance) is relatively low. For practicalapplications, capacitors require both high gravimetric and highvolumetric capacitance. For devices that are constrained with respect tosize, volumetric capacitance can be increased by more densely packingthe activated carbon particles. Traditional milling of activated carbonmaterials yields powders having a distribution of particle sizes and awide and random range of structures (i.e., non-spherical particleshapes). These characteristics limit the ability of activated carbonpowders to be densely packed, thus limiting the volumetric capacitancethat can be achieved by the same.

The present inventors have discovered that the density (i.e., particlepacking) of carbon materials can be improved by blending differentparticle size distributions obtained from different carbon materialsand/or from different milling operations. Since the particle sizedistributions in these various carbon materials can be different (e.g.,location of the peak size and/or the spread between minimum and maximumparticle size), blending of different carbon materials comprisingdifferent particle size distributions to obtain optimized packing can bequite difficult. The present inventors have solved this problem byemploying computer aided application of the modified Andreason equation(Eq. 2) for blending two or more carbon samples comprising differentparticle size distributions to improve the packing and hence thevolumetric performance of a capacitor comprising the blended carbonmaterial. Such techniques and resulting carbon materials representimprovements over known techniques and carbon materials.

By controlling the particle size distribution of the carbon particles,enhanced packing of the particles can be achieved. To this end, a numberof different models have been proposed for the optimum packing ofmultisized particles. Two equations in this regard are the formulasprovided by Furnas (C. C. Furnas, “Grading Aggregates: I”, Ind. Eng.Chem. 23:1052-58, 1931; F. O. Anderegg, “Grading Aggregates: II”, Ind.Eng. Chem. 23:1058-64), and Andreassen (A. H. M. Andreassen and J.Andersen, Kolloid Z. 50:217-228, 1931). Furnas' equation assumes theaddition of particles of smaller and smaller size, while Andreassen'sequation assumes the addition of particles of larger and larger size.Further, since the Furnas equation provides a theoretical distribution,while that of Andreassen is semi-empirical, the Andreassen equation hasbeen criticized for implying an infinite distribution with no minimumparticle size.

To address this shortcoming, a modified equation has been developed thatlinks the Furnas and Andreassen equations, referred to as the “modifiedAndreassen equation” or the “Dinger-Funk equation” (D. R. Dinger and J.E. Funk, Interceram 41(5):332-334, 1992). While the Andreassen equationgives a straight line on a logarithmic plot, the modified Andreassenequation gives a downward curvature since it takes into account aminimum particle size (d_(m)) of the distribution. The Andreassenequation (1) and the modified Andreassen equation (2) are presentedbelow:

$\begin{matrix}{{CPFT} = {\left( \frac{d}{D} \right)^{q}*100}} & \left( {{Eq}.\mspace{14mu} 1} \right) \\{{CPFT} = {\frac{\left( {d^{q} - d_{m}^{q}} \right)}{\left( {D^{q} - d_{m}^{q}} \right)}*100}} & \left( {{Eq}.\mspace{14mu} 2} \right)\end{matrix}$wherein

CPFT=Cumulative Percent Finer Than (Cumulative Finer Volumedistribution);

d=Particle size;

d_(m)=Minimum particle size of the distribution;

D=Maximum particle size; and

q=Distribution coefficient (“q-value”).

It should be noted that the above minimum particle size distributionsare based on volumes. This requires that mixtures of powders withdifferent densities be converted to volumes in order to give volumepercent. An important feature of the modified Andreassen equation isinfluence of the q-value on packing. By computer simulations, themodified Andreassen equation describes 100% packing density for infinitedistributions when the q-value is 0.37 or lower (D. R. Dinger and J. E.Funk, Interceram 42(3):150-152, 1993). Of course, as has also beendescribed in the art, real-world systems are finite, and thus 100%packing density is only achievable in theory. For q-values about 0.37,some degree of porosity will be present. Thus, for optimum packing theq-value should not exceed 0.37 and typically ranges from 0.30 to 0.37for densely packed materials.

One method for accessing the particle packing properties of a carbonmaterial, or other energy storage material, is to compare a plot of thecumulative finer volume distribution vs. particle size for the carbonmaterial to the modified Andreassen equation curve. The correlationcoefficient (i.e., R value) of the carbon material curve relative to themodified Andreassen equation curve is an indicator of the extent ofpacking optimization within the carbon material. A correlationcoefficient of 1.0 relative to the modified Andreassen equation curvewould indicate that optimum packing of the carbon particles within thecarbon material has been achieved. Accordingly, in one embodiment, thecorrelation coefficient of a plot of the cumulative finer volumedistribution vs. particle size of a disclosed carbon material comprisesa correlation coefficient of 0.90 or greater, 0.95 or greater, 0.96 orgreater, 0.97 or greater, 0.98 or greater, 0.99 or greater or even 0.995or greater relative to the modified Andreassen equation for the givenparticle size distribution.

Another measure of the particle packing properties of an energy storagematerial is the packing ratio when incorporated into an electrode. Whilethis metric may not correlate directly with the data obtained bycomparing the particle size distribution to the modified Andreassenequation, it serves as another means to assess the packing efficiency ofenergy storage particles. The packing ratio is a measure of the densityof the finished electrode compared to the expected density based on themass and volume of the electrode components. A packing ratio of 1.0would indicate that optimized packing has been achieved. A packing ratioof less than one indicates that less than optimum packing has beenachieved, and a packing ratio of greater than one indicates that packingis optimized beyond that expected based on the mass and volume of thecombined electrode components.

Surprisingly, the present inventors have found that in some embodimentswhen the particle size distribution is optimized according to thedisclosed methods, the disclosed carbon materials comprise a highpacking ratio when incorporated into an electrode. For example, FIGS.13a and 13b are TEM images of electrodes prepared from a control carbon(13A) and a carbon having optimized particle packing properties (13B).The TEM images clearly show a higher carbon packing ratio in theoptimized carbon versus the control carbon.

In some embodiments, the packing ratio of the disclosed carbon materialseven exceeds 1.0. While not wishing to be bound by theory, oneexplanation for this unexpected result is that the unique mesoporosityof the carbon materials in combination with the particular particle sizedistributions of the carbon materials provides for insertion of carbonparticles into the mesopores of the carbon material, thus increasing thepacking ratio beyond 1.0. Such increased packing ratios provide forimproved volumetric performance relative to carbon materials comprisinga lower packing ratio. Accordingly, in some embodiments the disclosedcarbon materials comprise packing ratios of 0.95 or greater, 0.97 orgreater, 1.0 or greater, 1.05 or greater, 1.10 or greater, 1.15 orgreater or 1.20 or greater.

In addition to an increased packing ratio, the present inventors havesurprisingly discovered that carbon materials having optimized packingratios as disclosed herein have advantageously high calendar ratios. Thecalendar ratio is determined as a ratio of the thickness of an electrodeafter it is calendared (i.e., rolled flat) compared to the thicknessprior to calendaring (after coating and drying). For example, a calendarratio of 50% indicates the thickness of the electrode has decreased byone-half upon calendaring. A higher calendaring ratio allows preparationof electrodes comprising more carbon per unit volume, and hence a higherenergy density (i.e., volumetric capacity). Other known carbonelectrodes materials cannot be calendared to such high calendar ratiosand instead become brittle and delaminate from the electrode substrate.Accordingly, in some embodiments the presently disclosed carbonmaterials have a calendar ratio of at least 10%, at least 20%, at least30%, at least 35%, at least 40%, at least 45%, at least 50%, at least55% or at least 60%.

FIGS. 1A and 1B present the data for a representative (prior art)particle size distribution for an activated carbon material (denoted LotA) subjected to milling by methods known in the art. The particle sizedistribution of this sample is shown in FIG. 1A. Electrodes wereproduced from this milled, activated carbon, assembled into double layerultracapacitors, and tested for electrochemical performance according tomethods known in the art. The average weight of the electrode was 7.2 mg(average 14.4 for two electrodes) and a volume of 0.0201 cm³. Thepacking ratio was calculated as measured electrode density (based onmeasured electrode weights and electrode size) divided by theoreticalenvelope density (calculated as 1 over the sum of measured BET totalpore volume of 1.003 cc/g and carbon volume assuming 0.439 cc/g carbondensity).

Referring to FIG. 1B, the dashed-line curve represents the line forparticle size distribution that would achieve a modified Andreassenq-value of 0.3 (in range for optimal particle packing). The solid-linecurve represents the measured particle size distribution of Lot A. Asshown in FIG. 1B, the actual measured particle size distribution issignificantly different from the theoretically optimal curve. For lot A,the correlation coefficient for the particle size data curve compared tothe Andreasson curve was about 0.94.

The milled activated carbon material of FIG. 1A (Lot A) was then subjectto additional milling by jet milling to yield Lot B. Lot B was thensubjected to further jet milling to yield Lot C. FIGS. 2A and 2B showthe PSD of Lot B and Lot C, respectively. Each additional milling stepresulted in a further reduction in particle size and a different PSD.For Lot B, the correlation coefficient for the particle size data curvecompared to the Andreasson curve was about 0.95.

FIG. 3A shows the resulting PSD of an approximately 40:60 blend of Lot Aand Lot B (the blended lot is denoted as Lot D). A plot of the predictedcorrelation coefficient calculated by the model vs. the ratio ofFraction of Lot A blended with lot B is presented in FIG. 3B. As can beseen, the incidence where the ratio is about 40-50% of Lot A blendedwith lot B provides for a maximization of the correlation coefficient(correlation coefficient achieved above about 0.98).

Referring to FIG. 3C, the dashed-line curve represents the line forparticle size distribution that would achieve a modified Andreassenq-value of 0.3 (in range for optimal particle packing). The solid-linecurve represents the measured particle size distribution of the blendedparticles of Lot D. As shown in FIG. 3C, the actual measured particlesize distribution is much closer to the optimal curve and has acorrelation coefficient of about over 0.98 relative to the modifiedAndreassen equation curve. Significantly, there was an increase inpacking density (1.16 for Lot D versus 1.01 for Lot A) and an increasein volumetric capacitance (20.6 F/cc @ 0.5 A/g for Lot D versus 19.0F/cc for Lot A). Further details of the electrochemical data for someblended carbon materials are presented in Table 1.

TABLE 1 Electrochemical Testing of Carbon Materials Having DifferentPacking Densities Elect. Vol. Cap. Grav. Cap. wt (F/cc +/− % STD) (F/g+/− % STD) (mg +/− (at 0.5, 1, 4 and 8 A/g, (at 0.5, 1, 4 and 8 A/g No.% STD) respectively) respectively) Lot 14.89 19.0 18.4 15.0 10.1 102.099.0 80.6 54.0 A +/− +/− +/− +/− +/− +/− +/− +/− +/− 2.5 2.4 2.5 5.015.5 4.7 4.8 6.9 17.7 Lot 15.8 20.6 19.7 14.7 9.2 104.5 99.8 77.4 47.0 D+/− +/− +/− +/− +/− +/− +/− +/− +/− 2.9 3.8 3.0 3.1 16.9 0.9 0.1 6.019.7

FIG. 4A shows the particle size distribution of the individualcomponents of a blend of particles comprised of about 40% Lot A (solidline) and 60% Lot C (dashed line), while FIG. 4B shows the resulting PSDof the blended particles (Lot E). Referring to FIG. 4C, the dashed-linecurve represents the line for particle size distribution that wouldachieve a modified Andreassen q-value of 0.3 (in range for optimalparticle packing). The solid-line curve represents the measured particlesize distribution of the blended particles of Lot E. As shown in FIG.4C, the actual measured particle size distribution closely follows theoptimal curve and has a correlation coefficient of about 0.97 relativeto the modified Andreassen equation curve. It was calculated that blendscomprising in the range of 40:60 to 80:20 Lot A:Lot C providedcorrelation coefficients above about 0.97. It was further calculatedthat blends comprising in the range of 50:50 to 70:30 Lot A:Lot Cprovided correlation coefficients above about 0.98.

FIG. 5A shows the particle size distribution of the individualcomponents of a blend of particles comprised of about 38% Lot A (solidline), 22% of Lot B (dashed line), and 40% Lot C (dotted line), whileFIG. 5B shows the resulting PSD of the blended particles (Lot F).Referring to FIG. 5C, the dashed-line curve represents the line forparticle size distribution that would achieve a modified Andreassenq-value of 0.3 (in range for optimal particle packing). The solid-linecurve shows the measured particle size distribution of the blendedparticles of Lot F. As shown in FIG. 5C, actual measured particle sizedistribution closely follows the optimal curve.

The particle size distribution of the carbon materials is an importantfactor in their electrochemical performance. In some embodiments, thecarbon materials comprise a plurality of carbon particles havingparticle sizes ranging from about 0.01 μm to about 50 μm. In otherembodiments, the particle size distribution comprises particle sizesranging from about 0.01 to about 20 μm. For example, in some embodimentsthe particle size distribution comprises particle sizes ranging fromabout 0.03 μm to about 17 or from about 0.04 μm to about 12 μm. Incertain embodiments of the foregoing, at least 90%, at least 95% or atleast 99% of the carbon particles having particles sizes in the range ofabout 0.01 μm to about 50 μm, about 0.01 μm to about 20 μm, about 0.03μm to about 17 μm or about 0.04 μm to about 12 μm.

While not wishing to be bound by theory, it is believed that a trimodalparticle size distribution similar to that shown in FIG. 5B provides foroptimal particle packing, and thus energy density, of the carbonmaterials. Accordingly, one embodiment provides a carbon material havinga particle size distribution as shown in FIG. 5B. For example, in someembodiments the carbon materials comprise a trimodal particle sizedistribution having first, second and third particle size maxima. Thefirst particle size maximum may range from about 0.08 μm to about 0.2μm, for example from about 0.09 to about 0.2 μm, from about 0.1 μm toabout 0.2 μm or from about 0.1 μm to about 0.15 μm. The second particlesize maximum may range from about 0.8 to about 2.0 μm, from about 0.8 μmto about 1.5 μm or from about 0.9 μm to about 1.0 μm. The third particlesize maximum may range from about 7.0 μm to about 15.0 μm, from about8.0 μm to about 12.0 μm or from about 9.0 μm to about 10.0 μm.

Alternatively, the particle size of the various carbons comprising thehighly packed electrode can be described in terms of their size relativeto the electrode thickness. For instance, a highly packed bimodalparticle distribtution comprised of particles with a first collection ofparticles of mean particle size A μm and a second collection ofparticles with mean size B μm and an electrode thickness C μm. In oneembodiment, the particles are comprised such that A:B is between about100:1 and 2:1, for example between about 50:1 and 5:1, for example about10:1; and C:A is between about 2:1 and 100:1, for example between about2:1 and 10:1, for example about 5:1.

In another embodiment, the carbon materials comprise a highly packedtrimodal particle distribution comprised of particles with a firstcollection of particles of mean particle size A μm and a secondcollection of particles with mean size B μm and a third collection ofparticles with mean size C μm and an electrode thickness D μm. In oneembodiment, the particles are comprised such that A:B and B:C arebetween about 100:1 and 2:1, for example between about 50:1 and 5:1, forexample about 10:1; and D:A is between about 2:1 and 100:1, for examplebetween about 2:1 and 10:1, for example about 5:1.

Applicants have also discovered the tap density of the carbon materialsto be unexpectedly high. In this regard, the high tap densities are alsobelieved to contribute, at least in part, to the unexpectedly highenergy densities of the carbon materials. In some embodiments, thedisclosed carbon material has a tap density between 0.2 and 0.6 g/cc,between 0.3 and 0.5 g/cc or between 0.4 and 0.5 g/cc. In anotherembodiment, the disclosed carbon material has a total pore volume of atleast 0.5 cm³/g, at least 0.7 cm³/g, at least 0.75 cm³/g, at least 0.9cm³/g, at least 1.0 cm³/g, at least 1.1 cm³/g, at least 1.2 cm³/g, atleast 1.3 cm³/g, at least 1.4 cm³/g, at least 1.5 cm³/g, at least 1.6cm³/g, at least 1.7 cm³/g, at least 1.8 cm³/g, at least 1.9 cm³/g or atleast 2.0 cm³/g.

Applicants have also discovered that the composition of matter describedherein achieves unexpected increase to extremely high carbon surfacearea per unit volume. This surface area per unit volume is calculated asthe product of the carbon specific surface area (for example, asdetermined from nitrogen sorption methodology) and the tap density. Forexample, applicants have found that the internal carbon surface area perunit volume can be increased from about 460 m²/cc to about 840 m²/cc,representing about an 83% increase over other known carbons.

The energy storage materials may comprise a mixture of different typesof energy storage particles. For example, different types of energystorage particles include, but are not limited to, activated carbon,carbon black, graphite, lead, silicon, lithium, sulfur, Teflon andvarious oxides, for example lithium oxides. Accordingly, in oneembodiment the energy storage material comprises a mixture of at leasttwo different types of energy storage particles. The mixtures maycomprise: activated carbon and carbon black, activated carbon andgraphite, carbon black and graphite, activated carbon and lead, carbonblack and lead, graphite and lead, activated carbon and silicon, carbonblack and silicon, graphite and silicon, activated carbon and lithium,carbon black and lithium, graphite and lithium, activated carbon andsulfur, carbon black and sulfur, graphite and sulfur, activated carbonand metal oxide (e.g., lithium oxides), carbon black and metal oxide(e.g., lithium oxides), graphite and metal oxide (e.g., lithium oxides),activated carbon and Teflon®, carbon black and Teflon®, graphite andTeflon® or any combination thereof. One skilled in the art can readilyderive other mixtures of energy storage particles which are useful inthe context of the present disclosure.

C. Purity and Other Properties of the Disclosed Carbon Material

The disclosed methods for preparation of carbon materials provide forcarbon materials having high purity. In some embodiments, the carbonmaterials are amorphous. Electrodes comprising carbon materials havingresidual levels of various impurities (e.g., chlorine, sulfur, metals,etc.) are known to decrease the breakdown voltage of the electrolyte inwhich the electrodes are immersed. Thus, these electrodes must beoperated at lower voltages and have a shorter life span than devicescomprising higher purity carbon. Impurities in carbon electrodes arealso thought to contribute to degradation of other components within anEDLC or battery. For example the porous membrane which separates the twocarbon electrodes in an EDLC may be degraded by chlorine or otherimpurities within the carbon electrode.

While not wishing to be bound by theory, it is believed that the purityof the disclosed carbon materials is a function of its preparationmethod, and variation of the preparation parameters may yield carbonmaterials having different properties. The purity of the disclosedcarbon materials can be determined by any number of techniques known inthe art. One particular method useful in carrying out the invention isproton induced x-ray emission (PIXE). This technique is very sensitiveand capable of detecting the presence of elements having atomic numbersranging from 11 to 92 (i.e., PIXE impurities) at the low PPM level.Methods for determining impurity levels via PIXE are well known in theart.

The disclosed carbon materials comprise low total PIXE impurities. Thus,in some embodiments the total PIXE impurity content in the disclosedcarbon material (as measured by proton induced x-ray emission) is lessthan 1000 ppm. In other embodiments, the total PIXE impurity content inthe disclosed carbon material is less than 800 ppm, less than 500 ppm,less than 300 ppm, less than 200 ppm, less than 150 ppm, less than 100ppm, less than 50 ppm, less than 25 ppm, less than 10 ppm, less than 5ppm or less than 1 ppm. In further embodiments of the foregoing, thedisclosed carbon material is a pyrolyzed dried polymer gel, a pyrolyzedpolymer cryogel, a pyrolyzed polymer xerogel, a pyrolyzed polymeraerogel, an activated dried polymer gel, an activated polymer cryogel,an activated polymer xerogel or an activated polymer aerogel.

In addition to low PIXE impurity content, the disclosed carbon materialscomprise high total carbon content. In addition to carbon, the disclosedcarbon material may also comprise oxygen, hydrogen and nitrogen. In someembodiments, the disclosed carbon material comprises at least 85%carbon, at least 90% carbon, at least 95% carbon, at least 96% carbon,at least 97% carbon, at least 98% carbon or at least 99% carbon on aweight/weight basis. In some other embodiments, disclosed carbonmaterial comprises less than 10% oxygen, less than 5% oxygen, less than3.0% oxygen, less than 2.5% oxygen, less than 1% oxygen or less than0.5% oxygen on a weight/weight basis. In other embodiments, thedisclosed carbon material comprises less than 10% hydrogen, less than 5%hydrogen, less than 2.5% hydrogen, less than 1% hydrogen, less than 0.5%hydrogen or less than 0.1% hydrogen on a weight/weight basis. In otherembodiments, the disclosed carbon material comprises less than 5%nitrogen, less than 2.5% nitrogen, less than 1% nitrogen, less than 0.5%nitrogen, less than 0.25% nitrogen or less than 0.01% nitrogen on aweight/weight basis. The oxygen, hydrogen and nitrogen content of thedisclosed carbon materials can be determined by combustion analysis.Techniques for determining elemental composition by combustion analysisare well known in the art.

The total ash content of a carbon material may, in some instances, havean effect on the electrochemical performance of a carbon material.Accordingly, in some embodiments, the ash content of the disclosedcarbon material ranges from 0.1% to 0.001%, for example in some specificembodiments the ash content of the disclosed carbon material is lessthan 0.1%, less than 0.08%, less than 0.05%, less than 0.03%, than0.025%, less than 0.01%, less than 0.0075%, less than 0.005% or lessthan 0.001%.

In other embodiments, the disclosed carbon material has a total PIXEimpurity content of less than 500 ppm and an ash content of less than0.08%. In further embodiments, the disclosed carbon material has a totalPIXE impurity content of less than 300 ppm and an ash content of lessthan 0.05%. In other further embodiments, disclosed carbon material hasa total PIXE impurity content of less than 200 ppm and an ash content ofless than 0.05%. In other further embodiments, the disclosed carbonmaterial has a total PIXE impurity content of less than 200 ppm and anash content of less than 0.025%. In other further embodiments, thedisclosed carbon material has a total PIXE impurity content of less than100 ppm and an ash content of less than 0.02%. In other furtherembodiments, the disclosed carbon material has a total PIXE impuritycontent of less than 50 ppm and an ash content of less than 0.01%.

The amount of individual PIXE impurities present in the disclosed carbonmaterials can be determined by proton induced x-ray emission. IndividualPIXE impurities may contribute in different ways to the overallelectrochemical performance of the disclosed carbon materials. Thus, insome embodiments, the level of sodium present in the disclosed carbonmaterial is less than 1000 ppm, less than 500 ppm, less than 100 ppm,less than 50 ppm, less than 10 ppm, or less than 1 ppm. In someembodiments, the level of magnesium present in the disclosed carbonmaterial is less than 1000 ppm, less than 100 ppm, less than 50 ppm,less than 10 ppm, or less than 1 ppm. In some embodiments, the level ofaluminum present in the disclosed carbon material is less than 1000 ppm,less than 100 ppm, less than 50 ppm, less than 10 ppm, or less than 1ppm. In some embodiments, the level of silicon present in the disclosedcarbon material is less than 500 ppm, less than 300 ppm, less than 100ppm, less than 50 ppm, less than 20 ppm, less than 10 ppm or less than 1ppm. In some embodiments, the level of phosphorous present in thedisclosed carbon material is less than 1000 ppm, less than 100 ppm, lessthan 50 ppm, less than 10 ppm, or less than 1 ppm. In some embodiments,the level of sulfur present in the disclosed carbon material is lessthan 1000 ppm, less than 100 ppm, less than 50 ppm, less than 30 ppm,less than 10 ppm, less than 5 ppm or less than 1 ppm. In someembodiments, the level of chlorine present in disclosed carbon materialis less than 1000 ppm, less than 100 ppm, less than 50 ppm, less than 10ppm, or less than 1 ppm. In some embodiments, the level of potassiumpresent in disclosed carbon material is less than 1000 ppm, less than100 ppm, less than 50 ppm, less than 10 ppm, or less than 1 ppm. Inother embodiments, the level of calcium present in the disclosed carbonmaterial is less than 100 ppm, less than 50 ppm, less than 20 ppm, lessthan 10 ppm, less than 5 ppm or less than 1 ppm. In some embodiments,the level of chromium present in the disclosed carbon material is lessthan 1000 ppm, less than 100 ppm, less than 50 ppm, less than 10 ppm,less than 5 ppm, less than 4 ppm, less than 3 ppm, less than 2 ppm orless than 1 ppm. In other embodiments, the level of iron present in thedisclosed carbon material is less than 50 ppm, less than 20 ppm, lessthan 10 ppm, less than 5 ppm, less than 4 ppm, less than 3 ppm, lessthan 2 ppm or less than 1 ppm. In other embodiments, the level of nickelpresent in the disclosed carbon material is less than 20 ppm, less than10 ppm, less than 5 ppm, less than 4 ppm, less than 3 ppm, less than 2ppm or less than 1 ppm. In some other embodiments, the level of copperpresent in the disclosed carbon material is less than 140 ppm, less than100 ppm, less than 40 ppm, less than 20 ppm, less than 10 ppm, less than5 ppm, less than 4 ppm, less than 3 ppm, less than 2 ppm or less than 1ppm. In yet other embodiments, the level of zinc present in thedisclosed carbon material is less than 20 ppm, less than 10 ppm, lessthan 5 ppm, less than 2 ppm or less than 1 ppm. In yet otherembodiments, the sum of all PIXE impurities, excluding sodium,magnesium, aluminum, silicon, phosphorous, sulphur, chlorine, potassium,calcium, chromium, iron, nickel, copper and zinc, present in thedisclosed carbon material is less than 1000 ppm, less than 500 μm, lessthan 300 ppm, less than 200 ppm, less than 100 ppm, less than 50 ppm,less than 25 ppm, less than 10 ppm or less than 1 ppm. As noted above,in some embodiments other impurities such as hydrogen, oxygen and/ornitrogen may be present in levels ranging from less than 10% to lessthan 0.01%.

In some embodiments, the disclosed carbon material comprises PIXEimpurities near or below the detection limit of the proton induced x-rayemission analysis. For example, in some embodiments the disclosed carbonmaterial comprises less than 50 ppm sodium, less than 15 ppm magnesium,less than 10 ppm aluminum, less than 8 ppm silicon, less than 4 ppmphosphorous, less than 3 ppm sulfur, less than 3 ppm chlorine, less than2 ppm potassium, less than 3 ppm calcium, less than 2 ppm scandium, lessthan 1 ppm titanium, less than 1 ppm vanadium, less than 0.5 ppmchromium, less than 0.5 ppm manganese, less than 0.5 ppm iron, less than0.25 ppm cobalt, less than 0.25 ppm nickel, less than 0.25 ppm copper,less than 0.5 ppm zinc, less than 0.5 ppm gallium, less than 0.5 ppmgermanium, less than 0.5 ppm arsenic, less than 0.5 ppm selenium, lessthan 1 ppm bromine, less than 1 ppm rubidium, less than 1.5 ppmstrontium, less than 2 ppm yttrium, less than 3 ppm zirconium, less than2 ppm niobium, less than 4 ppm molybdenum, less than 4 ppm, technetium,less than 7 ppm rubidium, less than 6 ppm rhodium, less than 6 ppmpalladium, less than 9 ppm silver, less than 6 ppm cadmium, less than 6ppm indium, less than 5 ppm tin, less than 6 ppm antimony, less than 6ppm tellurium, less than 5 ppm iodine, less than 4 ppm cesium, less than4 ppm barium, less than 3 ppm lanthanum, less than 3 ppm cerium, lessthan 2 ppm praseodymium, less than 2 ppm, neodymium, less than 1.5 ppmpromethium, less than 1 ppm samarium, less than 1 ppm europium, lessthan 1 ppm gadolinium, less than 1 ppm terbium, less than 1 ppmdysprosium, less than 1 ppm holmium, less than 1 ppm erbium, less than 1ppm thulium, less than 1 ppm ytterbium, less than 1 ppm lutetium, lessthan 1 ppm hafnium, less than 1 ppm tantalum, less than 1 ppm tungsten,less than 1.5 ppm rhenium, less than 1 ppm osmium, less than 1 ppmiridium, less than 1 ppm platinum, less than 1 ppm silver, less than 1ppm mercury, less than 1 ppm thallium, less than 1 ppm lead, less than1.5 ppm bismuth, less than 2 ppm thorium, or less than 4 ppm uranium.

In some specific embodiments, the disclosed carbon material comprisesless than 100 ppm sodium, less than 300 ppm silicon, less than 50 ppmsulfur, less than 100 ppm calcium, less than 20 ppm iron, less than 10ppm nickel, less than 140 ppm copper, less than 5 ppm chromium and lessthan 5 ppm zinc as measured by proton induced x-ray emission. In otherspecific embodiments, the disclosed carbon material comprises less than50 ppm sodium, less than 30 ppm sulfur, less than 100 ppm silicon, lessthan 50 ppm calcium, less than 10 ppm iron, less than 5 ppm nickel, lessthan 20 ppm copper, less than 2 ppm chromium and less than 2 ppm zinc.

In other specific embodiments, disclosed carbon material comprises lessthan 50 ppm sodium, less than 50 ppm silicon, less than 30 ppm sulfur,less than 10 ppm calcium, less than 2 ppm iron, less than 1 ppm nickel,less than 1 ppm copper, less than 1 ppm chromium and less than 1 ppmzinc.

In some other specific embodiments, disclosed carbon material comprisesless than 100 ppm sodium, less than 50 ppm magnesium, less than 50 ppmaluminum, less than 10 ppm sulfur, less than 10 ppm chlorine, less than10 ppm potassium, less than 1 ppm chromium and less than 1 ppmmanganese.

The disclosed carbon materials comprise a high surface area. While notwishing to be bound by theory, it is thought that such high surface areamay contribute, at least in part, to the high energy density obtainedfrom devices comprising the carbon material. Accordingly, in someembodiment, the disclosed carbon material comprises a BET specificsurface area of at least 150 m²/g, at least 250 m²/g, at least 400 m²/g,at least 500 m²/g, at least 600 m²/g, at least 700 m²/g, at least 800m²/g, at least 900 m²/g, at least 1000 m²/g, at least 1500 m²/g, atleast 2000 m²/g, at least 2400 m²/g, at least 2500 m²/g, at least 2750m²/g or at least 3000 m²/g. For example, in some embodiments of theforegoing, the disclosed carbon material is activated.

In another embodiment, the disclosed carbon material has a tap densitybetween 0.2 and 0.6 g/cc, between 0.3 and 0.5 g/cc or between 0.4 and0.5 g/cc. In another embodiment, the disclosed carbon material has atotal pore volume of at least 0.5 cm³/g, at least 0.7 cm³/g, at least0.75 cm³/g, at least 0.9 cm³/g, at least 1.0 cm³/g, at least 1.1 cm³/g,at least 1.2 cm³/g, at least 1.3 cm³/g, at least 1.4 cm³/g, at least 1.5cm³/g or at least 1.6 cm³/g.

The pore size distribution of the disclosed carbon materials is oneparameter that may have an effect on their electrochemical performance.For example, a carbon material comprising pores sized to accommodatespecific electrolyte ions may be particularly useful in EDLC devices. Inaddition, carbon materials comprising mesopores with a short effectivelength (i.e., less than 10 nm, less than 5, nm or less than 3 nm asmeasured by TEM) may be useful to enhance ion transport and maximizepower. Accordingly, in one embodiment, the disclosed carbon materialcomprises a fractional pore volume of pores at or below 100 nm thatcomprises at least 50% of the total pore volume, at least 75% of thetotal pore volume, at least 90% of the total pore volume or at least 99%of the total pore volume. In other embodiments, the disclosed carbonmaterial comprises a fractional pore volume of pores at or below 20 nmthat comprises at least 50% of the total pore volume, at least 75% ofthe total pore volume, at least 90% of the total pore volume or at least99% of the total pore volume.

In another embodiment, the disclosed carbon material comprises afractional pore surface area of pores at or below 100 nm that comprisesat least 50% of the total pore surface area, at least 75% of the totalpore surface area, at least 90% of the total pore surface area or atleast 99% of the total pore surface area. In another embodiment, thedisclosed carbon material comprises a fractional pore surface area ofpores at or below 20 nm that comprises at least 50% of the total poresurface area, at least 75% of the total pore surface area, at least 90%of the total pore surface area or at least 99% of the total pore surfacearea.

In another embodiment of the present disclosure, the disclosed carbonmaterial is prepared by a method disclosed herein, for example, in someembodiments the disclosed carbon material is prepared by a methodcomprising pyrolyzing a dried polymer gel as disclosed herein. In someembodiments, the pyrolyzed polymer gel is further activated to obtain anactivated carbon material.

The structural properties of the disclosed carbon materials may bemeasured using Nitrogen sorption at 17K, a method known to those ofskill in the art. The Micromeretics ASAP 2020 may be used to performdetailed micropore and mesopore analysis. The system produces a nitrogenisotherm starting at a pressure of 10⁻⁷ atm, which enables highresolution pore size distributions in the sub 1 nm range. The softwaregenerated reports utilize a Density Functional Theory (DFT) method tocalculate properties such as pore size distributions, surface areadistributions, total surface area, total pore volume, and pore volumewithin certain pore size ranges.

D. Use of the Disclosed Carbon Materials

The disclosed carbon materials can be used in devices requiring stable,high surface area micro- and mesoporous structure. Examples ofapplications for the disclosed carbon materials include, but are notlimited to: energy storage and distribution devices, ultracapacitorelectrodes, pseudocapacitor electrodes, battery electrodes, lithium ionanodes, lithium ion cathodes, lithium-carbon capacitor electrodes, leadacid battery electrodes, gas diffusion electrodes, including lithium-airelectrodes and zinc-air electrodes, lithium ion batteries and capacitors(for example as cathode material), conducting currentcollectors/scaffolds for other active materials in electrochemicalsystems, nanostructured material support scaffolds, solid state gasstorage (e.g., H₂ and CH₄ storage), adsorbents and as a carbon-basedscaffold support structure for other catalytic functions such ashydrogen storage or fuel cell electrodes.

The disclosed carbon materials may also be employed in kinetic energyharvesting applications such as: hybrid electric vehicles, heavyhybrids, all electric drive vehicles, cranes, forklifts, elevators,electric rail, hybrid locomotives and electric bicycles. The carbonmaterials may also be employed in electrical back-up applications suchas: UPS, data center bridge power, voltage dip compensation, electricbrake actuators, electric door actuators, electronics, telecom towerbridge power. Applications requiring pulse power in which the carbonmaterials of this disclosure may be useful include, but are not limitedto: boardnet stabilization, electronics including cell phones, PDAs,camera flashes, electronic toys, wind turbine blade pitch actuators,power quality/power conditioning/frequency regulation, electricsupercharger. Yet other uses of the carbon materials includes use inautomotive starting and stopping systems, power tools, flashlights,personal electronics, self contained solar powered lighting systems,RFID chips and systems, windfield developers for survey device power,sensors, pulse laser systems and phasers.

The disclosed carbon materials may also be used in applications wherehigh purity is critical, for example, applications in the medical,electronic, chemical analysis, mems (micromachines), and biologicalfields. Chemical and electrochemical sensors or detectors of all kindswould experience less interference from impurities or experience fewerside reactions caused or catalyzed by impurities. Examples areimpurities in air (explosives, hazardous chemicals, synthetic noses, orimpurities in water such as organics or water impurities in organicliquids.

The acid/base nature of carbon is largely a function of impuritiesincluding chemisorbed oxygen. Thus, carbon materials are useful inapplications where controlling the acid/base nature of the carbonmaterial is desired.

Carbon is used as a reactant in the chemical production of materials andas an electrode in the electrochemical production of materials. Thus,the disclosed carbon materials find utility in the chemical andelectrochemical production of high purity materials, especially metals.The disclosed carbon material may also be employed as an electrode inzinc-manganese oxide batteries (common flashlight batteries) andzinc-halogen batteries and incorporated into carbon-polymer compositesfor use as electrically conductive adhesives and seals and forminimizing radiation leakage.

1. Ultracapacitor Devices

EDLCs use electrodes immersed in an electrolyte solution as their energystorage element. Typically, a porous separator immersed in andimpregnated with the electrolyte ensures that the electrodes do not comein contact with each other, preventing electronic current flow directlybetween the electrodes. At the same time, the porous separator allowsionic currents to flow through the electrolyte between the electrodes inboth directions thus forming double layers of charges at the interfacesbetween the electrodes and the electrolyte.

When electric potential is applied between a pair of electrodes of anEDLC, ions that exist within the electrolyte are attracted to thesurfaces of the oppositely-charged electrodes, and migrate towards theelectrodes. A layer of oppositely-charged ions is thus created andmaintained near each electrode surface. Electrical energy is stored inthe charge separation layers between these ionic layers and the chargelayers of the corresponding electrode surfaces. In fact, the chargeseparation layers behave essentially as electrostatic capacitors.Electrostatic energy can also be stored in the EDLCS through orientationand alignment of molecules of the electrolytic solution under influenceof the electric field induced by the potential. This mode of energystorage, however, is secondary.

EDLCS comprising the disclosed carbon material, for example can beemployed in various electronic devices where high power is desired.Accordingly, in one embodiment an electrode comprising the disclosedcarbon materials is provided. In another embodiment, an ultracapacitorcomprising an electrode comprising the disclosed carbon materials isprovided.

The disclosed carbon materials find utility in any number of electronicdevices, for example wireless consumer and commercial devices such asdigital still cameras, notebook PCs, medical devices, location trackingdevices, automotive devices, compact flash devices, mobiles phones,PCMCIA cards, handheld devices, and digital music players.Ultracapacitors are also employed in heavy equipment such as: excavatorsand other earth moving equipment, forklifts, garbage trucks, cranes forports and construction and transportation systems such as buses,automobiles and trains.

As noted above, the present disclosure provides carbon materialsparticularly suited for improved volumetric performance whenincorporated into electrical storage and distribution devices (e.g.,EDLCs). Accordingly, in one embodiment, an ultracapacitor devicecomprising the disclosed carbon material having improved volumetricperformance is provided. In one embodiment, the ultracapacitorcomprising the disclosed carbon material comprises a gravimetriccapacitance in an organic electrolyte of at least 90 F/g, at least 100F/g, at least 102 F/g, at least 104 F/g, at least 106 F/g, at least 108F/g, at least 110 F/g, at least 115 F/g, at least 120 F/g, at least 125F/g or at least 130 F/g or at least 140 F/g, or at least, 150 F/g, or atleast 160 F/g. In another embodiment, an ultracapacitor devicecomprising the carbon material comprises a volumetric capacitance in anorganic electrolyte of at least 10 F/cc, at least 15 F/cc, at least 18F/cc, at least 20 F/cc, at least 21 F/cc, at least 22 F/cc, at least 23F/cc, at least 24 F/cc, at least 25 F/cc, at least 27 F/cc, at least 30F/cc or at least 35 F/cc. In some embodiments of the foregoing, thegravimetric capacitance and volumetric capacitance are measured byconstant current discharge from 2.7 V to 0.1 V with a 5-second timeconstant and employing a 1.8 M solution oftetraethylammonium-tetrafluororoborate in acetonitrile (1.8 M TEATFB inAN) electrolyte and a current density of 0.5 A/g, 1.0 A/g, 4.0 A/g or8.0 A/g.

In another embodiment, an ultracapacitor device comprising the disclosedcarbon material comprises a gravimetric power in an acetonitrile basedelectrolyte of at least 10 W/g, at least 15 W/g, at least 20 W/g, atleast 25 W/g, at least 30 W/g or at least 35 W/g. In another embodiment,an ultracapacitor device comprising the disclosed carbon materialcomprises a volumetric power in an acetonitrile based electrolyte of atleast 5 W/cc, at least 10 W/cc, at least 15 W/cc, at least 20 W/cc, atleast 25 W/cc or at least 30 W/cc. In another embodiment, anultracapacitor device comprising the disclosed carbon material comprisesa gravimetric energy in an organic electrolyte of at least 2.5 Wh/kg, atleast 5.0 Wh/kg, at least 7.5 Wh/kg, at least 10 Wh/kg, at least 12.5Wh/kg, at least 15.0 Wh/kg, at least 17.5. Wh/kg, at least 20.0 Wh/kg,at least 22.5 wh/kg or at least 25.0 Wh/kg. In another embodiment, anultracapacitor device comprising the disclosed carbon material comprisesa volumetric energy in an organic electrolyte of at least 1.5 Wh/liter,at least 3.0 Wh/liter, at least 5.0 Wh/liter, at least 7.5 Wh/liter, atleast 10.0 Wh/liter, at least 12.5 Wh/liter, at least 15 Wh/liter, atleast 17.5 Wh/liter, at least 20.0 Wh/liter, at least 25.0 Wh/liter orat least 30.0 Wh/liter.

In some embodiments of the foregoing, the gravimetric power, volumetricpower, gravimetric energy and volumetric energy of an ultracapacitordevice comprising the disclosed carbon material are measured by constantcurrent discharge from 2.7 V to 1.89 V employing a 1.0 M solution oftetraethylammonium-tetrafluororoborate in acetonitrile (1.0 M TEATFB inAN) electrolyte and a 0.5 second time constant.

In one embodiment, an ultracapacitor device comprising the disclosedcarbon material comprises a gravimetric power of at least 25 W/g, avolumetric power of at least 10.0 W/cc, a gravimetric energy of at least5.0 Wh/kg and a volumetric energy of at least 3.0 Wh/L.

In another embodiment, an ultracapacitor device comprising the disclosedcarbon material comprises a gravimetric power of at least 15 W/g, avolumetric power of at least 10.0 W/cc, a gravimetric energy of at least20.0 Wh/kg and a volumetric energy of at least 12.5 Wh/L.

In some embodiments, EDLC electrodes are prepared by blending thedisclosed carbon material with a fibrous Teflon binder (3% by weight) tohold the carbon particles together in a sheet. The carbon Teflon mixtureis kneaded until a uniform consistency is reached. Then the mixture isrolled into sheets using a high-pressure roller-former that results in afinal thickness of 50 microns. These electrodes are punched into discsand heated to 195° C. under a dry argon atmosphere to remove waterand/or other airborne contaminants. The electrodes are weighed and theirdimensions measured using calipers.

In some embodiments, the electrodes advantageously do not require use ofa conductivity enhancer for optimum energy density. Accordingly, certainelectrodes according to the present disclosure consist essentially ofthe disclosed blended carbon materials and a binder. For example,certain electrodes may comprise less than 1% conductivity enhancer oreven less than 0.1% conductivity enhancer. The present inventors believethis is the first example of a carbon electrode having such high energydensities without use of a conductivity enhancer.

The carbon electrodes of the EDLCs are wetted with an appropriateelectrolyte solution. Examples of solvents for use in electrolytesolutions for use in the devices of the present application include butare not limited to propylene carbonate, ethylene carbonate, butylenecarbonate, dimethyl carbonate, methyl ethyl carbonate, diethylcarbonate, sulfolane, methylsulfolane and acetonitrile. Such solventsare generally mixed with solute, including, tetralkylammonium salts suchas TEATFB (tetraethylammonium tetrafluoroborate); TEMATFB (tri-ethyl,methylammonium tetrafluoroborate); EMITFB (1-ethyl-3-methylimidazoliumtetrafluoroborate), tetramethylammonium or triethylammonium based salts.In some other embodiments, the electrolyte can be a water based acid orbase electrolyte such as mild sulfuric acid or potassium hydroxide.

In some embodiments, the electrodes are wetted with a 1.0 M solution oftetraethylammonium-tetrafluororoborate in acetonitrile (1.0 M TEATFB inAN) electrolyte. In other embodiments, the electrodes are wetted with a1.0 M solution of tetraethylammonium-tetrafluororoborate in propylenecarbonate (1.0 M TEATFB in PC) electrolyte. These are commonelectrolytes used in both research and industry and are consideredstandards for assessing device performance. In other embodiments, thesymmetric carbon-carbon (C—C) capacitors are assembled under an inertatmosphere, for example, in an Argon glove box, and a NKK porousmembrane 30 micron thick serves as the separator. Once assembled, thesamples may be soaked in the electrolyte for 20 minutes or moredepending on the porosity of the sample.

In some embodiments, the capacitance and power output are measured usingcyclic voltametry (CV), chronopotentiometry (CP) and impedancespectroscopy at various voltages (ranging from 1.0-2.5 V maximumvoltage) and current levels (from 1-10 mA) on an Biologic VMP3electrochemical workstation. In these embodiments, the capacitance maybe calculated from the discharge curve of the potentiogram using theformula:

$\begin{matrix}{C = \frac{I \times \Delta\; t}{\Delta\; V}} & \left( {{Eq}.\mspace{14mu} 3} \right)\end{matrix}$where I is the current (A) and ΔV is the voltage drop, Δt is the timedifference. Because in this embodiment the test capacitor is a symmetriccarbon-carbon (C—C) electrode, the specific capacitance is determinedfrom:C _(s)=2C/m _(e)  (Eq. 4)where m_(e) is the mass of a single electrode. The specific energy andpower may be determined using:

$\begin{matrix}{E_{s} = {\frac{1}{4}\frac{C\; V_{\max}^{2}}{m_{e}}}} & \left( {{Eq}.\mspace{14mu} 5} \right) \\{P_{s} = {{E_{s}/4}\;{ESR}}} & \left( {{Eq}.\mspace{14mu} 6} \right)\end{matrix}$where C is the measured capacitance V_(max) is the maximum test voltageand ESR is the equivalent series resistance obtained from the voltagedrop at the beginning of the discharge. ESR can alternately be derivedfrom impedance spectroscopy.

2. Batteries

The disclosed energy storage materials comprising optimized packingproperties also find utility as electrodes in any number of types ofbatteries. Batteries generally comprise powdered energy storagematerials in the form of an electrode. Such powdered energy storagematerials include, for example, activated carbon, graphite, mesoporouscarbon, titanate, silicon lithium compounds, germanium lithiumcompounds, aluminum lithium compounds, lithium cobalt oxide, lithiummanganese oxides, lithium nickel oxides, lithium iron phosphate, variousalloys of the above materials, mixtures of carbon and sulfur andmixtures of lithium and iron phosphate. Improved packing of thesebattery materials is expected to improve the performance of the battery.

Any number of other batteries, for example, zinc-carbon batteries,lithium/carbon batteries, lithium ion batteries, lithium sulfurbatteries, lead acid batteries and the like are also expected to performbetter if the particle packing properties of the energy storageparticles is optimized. Accordingly, in another embodiment the presentinvention provides a battery, in particular a zinc/carbon, alithium/carbon, a lithium ion, lithium sulfur or a lead acid batterycomprising a carbon material comprising optimized particles packingproperties. In some embodiments, the battery is a lithium ion batterycomprising oxide particles in the cathode and carbon particles in theanode. One skilled in the art will recognize other specific types ofbatteries, for example other carbon containing batteries, which willbenefit from the disclosed optimized packing of energy storageparticles.

EXAMPLES

The carbon materials disclosed in the following Examples were preparedaccording to the methods disclosed herein. Chemicals were obtained fromcommercial sources at reagent grade purity or better and were used asreceived from the supplier without further purification.

Unless indicated otherwise, the following conditions were generallyemployed. Phenolic compound and aldehyde were reacted in the presence ofa catalyst in a binary solvent system (e.g., water/acetic acid). Themolar ratio of phenolic compound to aldehyde was typically 0.5 to 1. Thereaction was allowed to incubate in a sealed glass ampoule at 90° C. forat least 24 hours or until gelation was complete. The resulting polymerhydrogel contained water, but no organic solvent; and was not subjectedto solvent exchange of water for an organic solvent, such as t-butanol.The polymer hydrogel monolith was then physically disrupted, for exampleby milling, to form polymer hydrogel particles having an averagediameter of less than about 30 mm. The particles were then rapidlyfrozen, generally by immersion in a cold fluid (e.g., liquid nitrogen orethanol/dry ice) and lyophilized. Generally, the lyophilizer shelf waspre-cooled to −50° C. before loading a tray containing the frozenpolymer hydrogel particles on the lyophilizer shelf. The chamberpressure for lyophilization was typically in the range of 50 to 1000mTorr and the shelf temperature was in the range of +10 to +25° C.Alternatively, the shelf temperature can be set lower, for example inthe range of 0 to +10° C. Alternatively, the shelf temperature can beset higher, for example in the range of +25 to +40° C.

The dried polymer hydrogel was typically pyrolyzed by heating in anitrogen atmosphere at temperatures ranging from 800-1200° C. for aperiod of time as specified in the examples. Activation conditionsgenerally comprised heating a pyrolyzed polymer hydrogel in a CO₂atmosphere at temperatures ranging from 900-1000° C. for a period oftime as specified in the examples. Specific pyrolysis and activationconditions were as described in the following examples.

Example 1 Preparation of Polymer Gels

According to the methods disclosed herein, a polymer gel was preparedfrom a binary solvent system comprised of water and acetic acid (75:25),resorcinol, formaldehyde, and ammonium acetate. The material was thenplaced at elevated temperature to allow for gellation to create apolymer gel. Polymer gel particles were then created from the polymergel and passed through a 4750 micron mesh sieve. The polymer gelparticles were frozen by immersion in liquid nitrogen, loaded into alyophilization tray at a loading of 3 to 7 g/in² and lyophilized. Thetime to dry (as inferred from time for product to reach within 2° C. ofshelf temperature) was related to the product loading on the lyophilizershelf.

The surface area of the dried gel was examined by nitrogen surfaceanalysis using a Micromeritics Surface Area and Porosity Analyzer (modelTriStar II). The measured specific surface area using the BET approachwas in the range of about 500 to 700 m²/g.

Example 2 Pyrolysis of Polymer Gels

Polymer gels prepared according to Example 1 were pyrolyzed viaincubation at 900° C. in a nitrogen atmosphere for a dwell time of 60min. The weight loss upon pyrolysis was 53±3%. In general, the specificsurface area of the pyrolyzed gel was similar to that for the driedpolymer gel before pyrolysis.

Example 3 Preparation of Activated Carbon Samples

Activated carbon samples were prepared from the pyrolyzed samplesprepared according to Example 2. The pyrolyzed carbon samples wereactivated by multiple passes through a rotary kiln (alumina tube with2.75 in inner diameter) at 900° C. under a CO₂ flow rate of 30 L/min,resulting in a total weight loss of about 45%.

The surface area of the activated carbon was examined by nitrogensurface analysis using a surface area and porosity analyzer. Themeasured specific surface area using the BET approach was in the rangeof about 1600 to 2000 m²/g.

Example 4 Preparation of Carbon Electrodes Having Optimized CarbonParticle Packing

Activated carbon was prepared as described in Example 3 and jet milledto produce two distinctly different particle size distributions. Theparticle size distributions of the two different samples (Fractions A(solid line) and B (dashed line)) are shown in FIG. 6.

A mathematical model was constructed to model blending these twoparticle size distributions by calculating the particle sizedistribution for the blend and calculating the correlation coefficientof the blend relative to the modified Andreassen equation for theparticle size distribution (q=0.3). In this context, the correlationcoefficient comparing the two curves has the usual definition known inthe art as a measure of the degree of interrelationship which existsbetween two curves, wherein r=1 represents ideal matching.

A plot of the correlation coefficient calculated by the model vs. theratio of Fraction A is presented in FIG. 7. As can be seen, for theindividual Fraction A material (case where Fraction A=1.0), thecorrelation coefficient was about 0.93. For this case, electrodes wereproduced, assembled into EDLCs and the electrochemical performance wasmeasured. In this case, the electrode density achieved was 0.775 g/cc,whereas the theoretical maximum electrode density (assuming totalabsence of any inter-particle void volume) was calculated as 0.845,resulting in an achieved packing ratio of about 0.92. This materialexhibited a volumetric capacitance of 19.1, 18.1, 12.7, and 7.2 F/cc at0.5, 1, 4 and 8 A/g current density, respectively.

As Fraction B material was blended with Fraction A materials, there wasan increase in the calculated correlation coefficient relative to theAndreassen curve, with the maximum correlation coefficient of about 0.97at a Fraction A value of 0.4. To test if improved packing could beachieved in practice, a carbon sample was prepared comprising a physicalmixture of 0.4 parts Fraction A and 0.6 part of Fraction B. In thiscase, the electrode density achieved was 0.836 g/cc, whereas thetheoretical maximum electrode density (assuming total absence of anyinter-particle void volume) was calculated as 0.845, resulting in anachieved packing ratio of about 0.99. Compared to the Fraction Amaterials, the optimally blended 40:60 Fraction A:Fraction B materialexhibited a markedly improved volumetric performance. Specifically, thismaterial exhibited a volumetric capacitance of 21.3, 20.0, 18.1, and12.7 F/cc at 0.5, 1, 4 and 8 A/g current density, respectively.Electrodes were tested in 1.8 M tetraethylene ammonium tetrafluoroboratein acetonitrile electrolyte.

Example 5 Preparation of Carbon Samples Having Optimized Packing

Activated carbon as described in Example 3 was jet milled in house. Themain sample was collected and analyzed for the particle sizedistribution, yielding the result shown in FIG. 8. Additional materialwas harvested from the bag house collector, which provided asubstantially lower particle size distribution (see FIG. 9). These twosamples were analyzed for their fit to the Andreasson equation (seeFIGS. 10 and 11, respectively). As described above, these two lots wereblended theoretically to determine the ratio which would result in thebest fit to the Andreasson equation.

It was determined that the optimal blend was comprised (by mass) ofabout 57% of the main sample (referred to herein as the “controlmaterial” or “control carbon”) and 43% of the bag house collectedmaterial (the “additional material” noted above). As shown in FIG. 12,this particular composition fits the Andreassen equation with an r²value of about 0.98, compared to lower values obtained for the controlmaterial alone (r² value about 0.96) or the bag house material alone (r²value about 0.83). An actual carbon blend was then prepared using thisexact composition.

Example 6 Correlation Coefficients of Commercial Carbon Samples

Several commercial carbons were obtained and their particle sizedistributions were measured. These data where compared using thecorrelation coefficient approach discussed in Example 4, i.e., comparedto the modified Andreassen equation (q=0.3) for the particle sizedistribution. The results are tabulated in Table 2 below.

TABLE 2 Correlation Coefficients of Commercial Carbon Samples CommercialCarbon Sample Correlation Coefficient #1 0.92 #2 0.95 #3 0.95 #4 0.87

Example 7 Dry Preparation of Electrodes and Capacitors Comprising theDisclosed Carbon Materials

Capacitor electrodes comprised 99 parts by weight carbon particles(average particle size 5-15 microns) and 1 part by weight Teflon.Optimized carbon blends as described herein and Teflon were masticatedin a mortar and pestle until the Teflon was well distributed and thecomposite had some physical integrity. After mixing, the composite wasrolled out into a flat sheet, approximately 50 microns thick. Electrodedisks, approximately 1.59 cm in diameter, were punched out of the sheet.The electrodes were placed in a vacuum oven attached to a dry box andheated for 12 hours at 195° C. This removed water adsorbed from theatmosphere during electrode preparation. After drying, the electrodeswere allowed to cool to room temperature, the atmosphere in the oven wasfilled with argon and the electrodes were moved into the dry box wherethe capacitors were made.

Capacitor coin cells for testing were prepared according to thefollowing general procedure: A positive cap is placed inside a guidering. One piece of conductivity enhancer is then placed in the center ofthe positive cap. A carbon electrode is placed on top of that. Thiselectrode is referred as cathode during charging up.

Using a glass dropper, 1M TEABF4/ACN electrolyte (or 1.8M TEMABF4/PCelectrolyte) is added onto the electrode/conductivity enhancer stack.The open space of positive cap is filled with electrolyte. Next, 1 pieceof NKK separator is placed into the positive cap on top of the electrodepiece. The separator should be soaked well with little gas bubble inbetween. A second electrode (heavier than the first) is placed in thecenter of the separator in a similar fashion to the separator. Thissecond electrode will be referred to as the anode during charging up.Several drops of electrolyte are added onto that to wet the abovesurface of the electrode.

A second piece of conductivity enhancer is then placed onto theelectrode followed by a metal spacer on top of the stack. The spacer isslightly pressed down with the tip of tweezers to drive out air bubbles.Next, a spring is placed on top of the spacer, and a negative cap withgasket is placed on to cover the whole stack. The cell stack is thencrimped to form the capacitor cell.

Example 8 Aqueous Slurry Preparation of Electrodes

Electrodes were prepared by mixing carbon samples (either the optimizedblend prepared according to Example 5 (“Blend”) or the control carbon(“CC”)) with a binder (“B”) (the binder in this example was LHB-108Pavailable from LICO Technology Corp.) and an optional conductivityenhancer (“CE”) (e.g., Super P, available from TIMCAL, Ltd., VulcanXC-72, available from Akrochem Corp, Akron Ohio, etc.). Three differentelectrodes were prepared according to the following mixing ratios:

Sample 1: 80% CC; 5% CE and 15% B;

Sample 2: 85% Blend and 15% B; and

Sample 3: 85% Blend and 15% B.

The above dry mixtures were added portionwise to water such that thefinal solid to solvent ratio was 1:2.5. Overhead mixing was used toensure effective mixing. The slurry was first mixed at 575 rpm, thenincreased to 725 rpm after ¼th the volume of carbon added. This wasrepeated every fourth of the way increasing the setting to 1050 rpm and1425 rpm, respectively. A homengenizer was used as needed (e.g., everytwenty minutes) to ensure effective mixing. Manual stirring was alsoused as required to provide external assistance in the homogenizingprocess, and the slurry was degassed as required (e.g., for one hour).Coin cells were then prepared as described in Example 7.

A summary of the electrode densities achieved is provided in Table 3.

TABLE 3 Characteristics of Electrodes Prepared from Various Blends PoreVolume of Elec- Max Activated Start End Cal. trode Theor. Actual Pack.Carbon Thick. Thick. Ratio wt Density Density Eff. No. (cc/g) (um) (um)(%) (mg) (g/cc) (g/cc) (%) 1 0.847 93 66 29% 19.68 0.99 0.742 75 2 0.94295 44 54% 14.81 0.83 0.837 100 3 0.942 98 40 59% 12.84 0.83 0.799 96

As can be seen, for the control sample (No. 1), it was only possible toachieve about 29% calendaring ratio (i.e., the ratio of the thickness ofthe electrode sheet after and before rolling), above this point, therewas delamination observed of the electrode off from the currentcollector. For the blend, three electrodes were produced, and it ispossible to achieve much higher calendaring ratios, up to as much asnearly 60%. For the control material, it was only possible to achieve adensity of about 0.74 g/cc, corresponding to about 75% of the maximumobtainable density based on pore volume of the carbon material (orpacking ratio of about 0.75). In dramatic contrast, for the optimizedblended materials, it was possible to achieve densities as high as 0.837g/cc, corresponding to up to 100% of the theoretical maximum density (orpacking ratio of about 1.00). FIGS. 13a and 13b are TEM images showingthe dramatic difference in densities between the control electrode (13a) and the electrode prepared with the optimized carbon blends disclosedherein (13 b).

Finally, the electrochemical performance was measured for the controlelectrode (No. 1), and electrode No. 2 (the blended material whereinabout 1.00 packing ratio was achieved). It was observed for the controlthat the gravimetric capacitance achieved was 102.9 F/g and thevolumetric capacitance achieved was 18.5 F/cc. For the blended carbonmaterial, there was a slight increase in the gravimetric capacitanceobserved, to 110.4 F/g (data for sample 2). In dramatic contrast, thevolumetric capacitance for the blended material was 23.1 F/cc (data forsample 2), representing an increase of about 25%, concomitant with the25% increase in density also achieved. Electrodes were tested in 1.8 Mtetraethylene ammonium tetrafluoroborate in acetonitrile electrolyte.

Example 9 Organic Slurry Preparation of Electrodes

Electrodes were prepared by making a slurry of: 1). 80% CC; 5% CE and15% B; or 2) 95% Blend and 5% B in an organic solvent(N-methylpyrrolidone (NMP)). The slurries were coated on an electrodesubstrate and dried in an oven.

Electrode thicknesses were measured and then each electrode wascalendared from the original thickness to 50 μm using a manual rollingpress. Electrodes comprising the blended carbon material had an originalthickness of 94 um which was reduced by 47% to a final thickness of 50μm. Electrodes comprising the control carbon had and original thicknessof 111 mm which was reduced by 55% to a final thickness of 50 μm.Surprisingly, electrodes prepared via a dry mixing process (i.e., not aslurry process as described in this example) were not calanderable to 50μm, although similar trends in electrode mass and volumetric performancewere observed for a dry electrode preparation.

The data in Table 4 shows that the average mass of an electrodecomprising the blend carbon was 29.4% greater than the average mass ofan electrode comprising the control carbon.

TABLE 4 Electrode Masses Avg. Mass Sample Carbon Mass (mg) (mg) 1 Blend12.94 12.98 2 Blend 12.86 3 Blend 13.00 4 Blend 12.83 5 Blend 13.25 6Control 9.31 9.17 7 Control 8.85 8 Control 9.05 9 Control 9.44 10Control 9.19

The electrodes in Table 4 were then tested for their electrochemicalperformance. Electrodes were tested in 1.8 M tetraethylene ammoniumtetrafluoroborate in acetonitrile electrolyte. The data presented inFIG. 14 show that volumetric capacitance increased from 12.5 F/cc at 0.5A/g in electrodes comprising the control carbon to 16.9 F/cc at 0.5 A/gin electrodes comprising the blended carbon (an increase of 26%). Thegravimetric capacitance was similar between control carbon electrodesand blended carbon electrodes (FIG. 15).

The various embodiments described above can be combined to providefurther embodiments. All of the U.S. patents, U.S. patent applicationpublications, U.S. patent applications, foreign patents, foreign patentapplications and non-patent publications referred to in thisspecification and/or listed in the Application Data Sheet, areincorporated herein by reference, in their entirety. Aspects of theembodiments can be modified, if necessary to employ concepts of thevarious patents, applications and publications to provide yet furtherembodiments. These and other changes can be made to the embodiments inlight of the above-detailed description. In general, in the followingclaims, the terms used should not be construed to limit the claims tothe specific embodiments disclosed in the specification and the claims,but should be construed to include all possible embodiments along withthe full scope of equivalents to which such claims are entitled.Accordingly, the claims are not limited by the disclosure.

The invention claimed is:
 1. A composition comprising an energy storagematerial and an electrolyte or a gas, the energy storage materialcomprising a plurality of energy storage particles, wherein theplurality of energy storage particles comprises a particle sizedistribution such that the equation of a plot of the cumulative finervolume distribution vs. particle size comprises a correlationcoefficient of 0.96 or greater relative to the modified Andreassenequation for the particle size distribution, and wherein the modifiedAndreassen equation comprises a q value of 0.3.
 2. The composition ofclaim 1, wherein the energy storage material comprises a carbonmaterial.
 3. The composition of claim 2, wherein the carbon materialcomprises activated carbon, carbon black or graphite.
 4. The compositionof claim 1, wherein the energy storage material comprises a carbonmaterial, lead, silicon, lithium, sulfur or combinations thereof.
 5. Thecomposition of claim 4, wherein the carbon material comprises activatedcarbon, carbon black or graphite.
 6. The composition of claim 1, whereinthe energy storage material comprises a carbon material and silicon. 7.The composition of claim 1, wherein the energy storage materialcomprises a carbon material and a lithium oxide.
 8. The composition ofclaim 1, wherein the composition comprises an electrolyte.
 9. Thecomposition of claim 8, wherein the electrolyte comprises lithium ions.10. The composition of claim 8, wherein the electrolyte comprises atetralkylammonium salt.
 11. The composition of claim 8, wherein theelectrolyte comprises an aqueous acid, an aqueous base or an organicsolvent.
 12. The composition of claim 11, wherein the organic solventcomprises propylene carbonate, ethylene carbonate, butylene carbonate,dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate,sulfolane, methylsulfolane, acetonitrile or mixtures thereof.
 13. Thecomposition of claim 8, wherein the electrolyte comprises atetraethylammonium or triethylammonium salt or combinations thereof. 14.The composition of claim 8, wherein the electrolyte comprises TEA TFB(tetraethylammonium tetrafluoroborate), MTEATFB (methyltriethylammoniumtetrafluoroborate), EMITFB (1 ethyl-3-methylimidazoliumtetrafluoroborate) or combinations thereof.
 15. The composition of claim1, wherein the composition comprises a gas.
 16. The composition of claim15, wherein the gas comprises hydrogen, methane or combinations thereof.17. The composition of claim 1, wherein the energy storage materialcomprises a carbon material, and the composition comprises anelectrolyte comprising lithium ions.
 18. The composition of claim 1,wherein the energy storage material comprises a carbon material andsilicon, and the composition comprises an electrolyte comprising lithiumions.
 19. The composition of claim 1, wherein the energy storagematerial comprises a carbon material, and the composition comprises agas comprising hydrogen.
 20. The composition of claim 1, wherein theenergy storage material comprises a carbon material, and the compositioncomprises a gas comprising methane.